Friday, October 31, 2008

Greenhouse - Auction Coming Up

Woodside Greenhouses (Denton/Ridgely MD area) is having a greenhouse business liquidation sale on November 8. This was a well run greenhouse business and the equipment is in good condition. Delaware greenhouse growers may be interested in going to the sale. The following is the list of what is being sold.

Greenhouses & Equipment, Tractors, Trucks, Forklift, Mower, Golf Cart, Generators, Mobile Home & Inventory

SATURDAY, NOVEMBER 8, 2008 10:00 A.M.

Location: Woodside Greenhouses - 24414 Deerfield Lane, Ridgely, MD. Traveling on MD-404 in Denton, Maryland, turn North at the light onto River Road. Proceed 8/10 mile and turn left onto Central Avenue. Continue 8/10 mile and turn left at Woodside Greenhouse onto Deerfield lane. Signs will be posted.

Greenhouses & Equipment: (3) 30' x 148' & (2) 27' 148' freestanding greenhouses each w/heater, exhaust fans, intake louvers, fan jet circulation fan, 275 gal oil tank, thermostats, temperature alarm, benches, cement blocks, electric service, hanging basket drip lines (approx 225-10" HB capacity) & 1 year old ploy covering. (1) 30' x 48' freestanding greenhouse w/Siebring oil heatmaster unit, exhaust fans, auto garage door, desks & counters. (2) 27' x 72' freestanding greenhouses w/polycarbonate end walls, heater exhaust fans, intake louvers, Fan Jet circulation fan, 275 gal oil tank, thermostats, temperature alarm, benches, cement blocks & electric service. (1) 30' x 72' freestanding greenhouse w/36" exhaust fans, 48" intake louvers, under bench hot water heating w/boiler, 4-HAF Fans, bench misting ysytem w/Phytronics controller, thermostats & electric service. (1) 20' x 72' disassembled greenhouse. (1) 20' x 72' freestanding greenhouse. (1) 27' x 48' freestanding greenhouse w/ benches, concrete blocks, fans, LP Unit heater & 1 year old ploy covering. (5) 20' x 148' freestanding greenhouses w/heater, exhaust fans, intake louvers, Fan Jet circulation fan, thermostats, temperature alarm, benches, cement blocks & electric service. (1) 27' x 48' four bay gutter connect greenhouse w/4 Unit heaters, 4-275 gal oil tanks, Wadsworth Step 50 controller, 8-48" exhaust fans, 8 intake louvers, inflation fans, HAF fans, benches, concrete blocks, hanging basket drip lines (approx 1300-10" HB capacity, polycarbonate end wall, retail display fixtures, counters & electric service. (8) 275 gal oil tanks. Greenhouses are to be removed from property by buyer within 90 days. Any extensions are subject to approval by owner. Soil Equipment: Bouldin & Lawson 1 yard soil mixer, Bouldin & Lawson 10' elevator/soil conveyor, Bouldin & Lawson pot filler, Add-A-Veyor drive w/3 additional sections. Carts: (32) shipping carts w/shelves & 8" pneumatic wheels.

Tractors, Trucks, Forklift, Mower, Golf Cart & Equipment: Kioti 18hp 4WD compact tractor w/bucket loader, White 75hp tractor w/pallet forks. 1989 International S1700 24' Box truck w/lift gate- 270,000 miles in good condition, 2004 Chevrolet cube van w/8' x 14' x 8' Bay Bridge box, pull out loading ramp & plant shelves-55,000 miles in excellent condition. Yale 5000 lb capacity LP forklift. John Deere 757 18hp Z Trak mower w/60" deck-330 hrs & in excellent condition. EZ Go golf cart. Tow Rite 10' single axle trailer, 18' flat bed wagon on John Deere running gear, Woods Cadet MD184-7' rotary mower, Woods XT148- 4' rotary mower, 8' pull type disk, 6' box scrape, King Kutter 6' scrape blade, Agrotec 150 gal airblast sprayer, Fimco 25 gal electric sprayer, ESS sprayer, LVM 100 Ball Fast sprayer, Pulsfog sprayer, Kruser 25 gal sprayer, Agri Fab lawn cart & more.

Generators, Mobile Home & Inventory: Kohler 60kw backup generator, John Deere 60kw backup generator. 1996 Fleetwood 14' x 50' mobile home with a/c, LP heat and major appliances. A large inventory of hanging baskets & hangers, 6"& 8" azalea pots, mum pots, trays and much more.

Thursday, October 30, 2008

Landscape and Nursery - Botryosphaeria Canker Pictures

The following are pictures of Botryosphaeria canker from several woody plant hosts. You may see an increase in this disease due to the stress placed on plants by a second year of summer drought.

Botryosphaeria canker on crabapple. Photo from University of Georgia Plant Pathology Archive, University of Georgia,

Botryosphaeria canker on green ash. Photo by Theodor D. Leininger, USDA Forest Service,

Botryosphaeria canker on Leyland Cypress. Photo by Robert L. Anderson, USDA Forest Service,

Landscape and Nursery - Botryosphaeria Canker

With the extra stress placed on woody landscape plants this year by the drought you can expect to see increased incidence of Botryosphaeria canker. The following is an article on the subject from Rutgers University.

Botryosphaeria canker is a commonly occurring disease that affects woody plants in over 100 genera. Although the disease is very important in fruit and nut crops, it can be troublesome in ornamental species such as ash, birch, cotoneaster, crabapple, dogwood, elm, firethorn, hop hornbeam, mountain laurel, locust, magnolia, mimosa, photinia, pieris, privet, rhododendron, and wax myrtle. The causal agent, Botryosphaeria dothidea, is an opportunistic fungus that attacks trees and shrubs wounded or weakened by environmental stress, particularly drought. The disease can result in a branch dieback that may kill trees or severely reduce their aesthetic value. Indeed, Botryosphaeria canker is quite evident now on older, stressed rhododendrons.

Symptoms of Botryosphaeria canker vary with the species and age of the host and the severity of the predisposing stress. The fungus kills bark and sapwood tissue, causing areas of dead tissue called cankers to form. Cankers range from small, elliptical lesions that coalesce into large diffuse areas of blighted tissue, to large, elongate cankers delimited by callus tissue. Affected bark turns dark, rough, and may peel away. Multiple cankers of various sizes often develop on branch tissue, growing slowly until the limb is girdled and killed. The entire plant may be killed once the canker moves from the branch into the main stem. Disease cycle Botryosphaeria survives the winter in small, round “fruiting bodies” (or structures that produce spores) embedded near the surface of cankered tissue. Infections occur when spores called conidia are splashed by rain from these fruiting bodies to susceptible tissue. Spore dispersal can occur during most of the year, but is most extensive during late spring and early summer. Infection occurs when fungal spores penetrate wounds or other openings in the bark. Pruning wounds, cracks, leaf scars, sunscald lesions, and senescent branches are all good entry sites for the fungus. Symptom development can take anywhere from 3 months to a year.

Through careful monitoring and early detection, Botryosphaeria canker can be eradicated before a significant reduction in the aesthetic value of the tree occurs. Branches with symptoms of canker should be promptly pruned during dry weather at least 6 to 8 inches below affected tissue. If possible, remove the branch from the tree by properly cutting the limb flush to the branch collar, not flush to the trunk. To prevent the spread of this disease on pruning tools, surface-sterilize tools between cuts with denatured alcohol or 10% bleach. Since the fungus can persist and sporulate in dead plant material for extended periods, branches cut from diseased trees should be taken from the site and, if possible, composted. Fungicides or wound paints have not proven to be an effective control of most canker diseases and are not recommended.

Reprinted in part from "Botryosphaeria Canker: Troublesome to Plants in Dry Weather" by Ann B. Gould, Ph.D., Specialist in Plant Pathology, in the October 9, 2008 edition of the Plant and Pest Advisory, Landscape, Nursery, and Turf Edition from Rutgers University.

Wednesday, October 29, 2008

Prepare for Voles - Reducing Winter Damage

Voles can do considerable damage to landscape plants in the late fall and winter. The following is information on voles and how to reduce winter damage in landscapes.

Pine voles live primarily in shallow underground tunnels, but will sometimes forage aboveground. In addition to the damage done during winter, pine voles may cause damage throughout the growing season. Pine voles eat bulbs, tubers, seeds and bark (root bark included), but can damage a wide variety of other plants, including roses, fruit trees, flowers and vegetable garden plants. In many cases the damage from pine voles goes unnoticed until the owner discovers the decline or death of a particular plant. In vegetable gardens, entire plants may be pulled partially or entirely underground. Wilted plants with chewed roots are commonly observed. In flower and bulb gardens, plants may fail to grow in the spring after underground tubers, roots and bulbs have been consumed by pine voles.

Meadow voles prefer wetter soils than pine voles. They live primarily above ground, making shallow surface tunnels or runways. Meadow voles gnaw bark from trunk and branches of trees and shrubs during the winter and early spring. Deep snow cover allows for vole damage to extend higher on trees and shrubs. They also chew out crowns of herbaceous perennials and grasses, and chew out trails in the turf. These trails can be seen in turf or snow cover. Nests are made of interwoven strands of dry grass and contain caches of food. Unless the damage is severe, perennials and grasses will generally recover. As mentioned above under rabbit damage, the survival of woody stems partially girdled depends upon the extent of the damage. Often, deciduous shrubs will send up new shoots later in spring.

Keep grass and ground covers away from trunks of trees and shrubs. Voles require vegetation or other cover in order to survive. By eliminating or reducing this cover one reduces their preferred foods, exposes them to predators and exposes the animals to severe weather. In the home landscape, avoid deep mulching in gardens and plant beds where voles are known to be a problem. Certain mulches are more likely to attract voles than others; avoid using mulches with fine or small particle sizes. Large-sized crushed-stone mulch and pine bark mulch may reduce vole tunneling. Plastic and landscape fabric mulches may increase vole populations and subsequent damage. Frequent mowing of grass around trees and shrubs will help to reduce the potential for vole injury.

Reprinted from the March 19, 2004 edition of Landscape Alert Newsletter from Michigan State University.

Greenhouse - More on Lowering Heating Costs

The following is another short article on reducing greenhouse heating costs from Michigan State University.

Fuel costs for many greenhouses will be substantially higher than they’ve been in recent history, and perhaps ever. I have compiled a list of suggestions for how greenhouse operations can reduce energy consumption, accelerate crop development or improve space efficiency. Some of these suggestions require capital investment, but I believe in most situations, the return on investment can be significant.

Don’t cheat on heat

Crop timing increases as temperature decreases. If you plan to market the plants on the same date as in the past, then you need to begin growing the crop earlier, meaning you will have to start heating your greenhouse earlier. Energy consumption per crop grown in the spring can be higher when crops are grown cool because you have to heat the greenhouse for a longer period of time.

Use a retractable energy/shade curtain

Most of the energy consumed by a greenhouse is used for heating, and most (perhaps 80%) heating occurs at night. Deploying a retractable shade/energy curtain at night can significantly reduce heat loss by providing another insulating layer to the greenhouse.

Provide supplemental lighting to plugs

A majority of seedlings and cuttings are produced in late winter and early spring, when natural light levels in the northern half of the United States and Canada are low. Increasing the light level can accelerate crop development by increasing plant temperature and by reducing the number of leaves formed before the first flower develops.

Provide long days to long-day plants

Many bedding plants and perennials are long-day plants, meaning that they flower earlier when grown under a long photoperiod. Common examples of long-day plants include ageratum, blue salvia, dianthus, pansy, petunia, rudbeckia, snapdragon, and tuberous begonia. During the spring, the photoperiod is naturally short until April, so flowering of early long-day crops is delayed unless artificial long days are provided.

Improve insulation

Look for gaps near fans, pads and doors; make sure there are no holes or gaps in your roof; and consider adding an extra layer of insulation to your north wall. Just be mindful not to reduce incoming light too much – or the quality of your crops might be compromised.

Grow cold-tolerant and cold-sensitive crops separately

Not all plants respond to temperature the same way. Plants like vinca and celosia grow very slowly at 60°F (16°C) while other plants such as ageratum, pansy and ivy geranium continue to grow moderately well at this low temperature. Whenever possible, grow cold-tolerant crops in one greenhouse and cold-sensitive crops in a separate greenhouse.

Only open up a greenhouse when it can be filled

Once a greenhouse is opened for use in the early spring, heat needs to be used whether it is full of crops or not. If you have multiple ranges, try to schedule your spring crops so that you fill each greenhouse when first opened.

Use a larger plug size to reduce final crop timing

During the finish stage, there are fewer plants per square foot of greenhouse space compared to during the plug stage. Thus, heat and lighting costs per plant are lower when plants are grown at the higher plant density during the plug stage. By using a larger plug size, you could increase your plug stage duration and reduce the time of your finish stage.

Install horizontal air flow fans

Horizontal air flow fans not only mix warm air with cool air, but also improve the uniformity of temperature within the greenhouse. If you already have horizontal air flow fans installed, make sure they are all operating and are well positioned (i.e., not angled down towards crops or upwards towards the roof).

Increase your heat/vent deadband

You want to avoid frequent cooling/heating cycles, and the best way to do this is to increase the temperature deadband during the winter and spring. A slightly larger increase in the venting setpoint will allow you to take advantage of heating from the sun. Remember to monitor your average daily temperature and make adjustments as necessary to stay on track with your production schedule.

Reprinted from "Lower your spring heating bill" by Erik Runkle in the October, 2005 edition of the Greenhouse Alert Newsletter from Michigan State University.

Tuesday, October 28, 2008

Landscape - Pruning Knock Out Roses

Knock Out low maintenance free blooming shrub roses have been big hits in the nursery and landscape industry. I was recently asked about pruning knock out roses once planted in the landscape. This was my response:

In the year after planting, no pruning is really necessary if they are not too tall for the area planted in. As they grow in the landscape in future years, if they are taller than you like then head back in spring as low as 2 feet. You can practice renewal pruning with Knock Out roses but they will bloom well on old and new canes After 2 years you can start renewal pruning by removing a few of the oldest canes pruned to the ground level. Each year thereafter remove some of the oldest canes to the ground, keeping the newest ones. Again, this type of renewal pruning is not required for them to perform well. As always, remove any dead canes. You should do some heading back at least every 3 years but the amount that you prune back is not critical, 1/3 of the growth would be fine. Any extra tall, straight growth should be cut back by about 1/2. They should normally not get any higher than 5 feet unless in very fertile soil. For many areas you may not need to head back at all and may not need much pruning for several years. Pruning is done in spring although light pruning can be done also during the growing season.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

Greenhouse - Temperatures and Insects

Growing cooler in the greenhouse can limit the development of some insect pests. However, the effects vary with insect type. The following are some common grenhouse insect pests and the effects of temperature.

Western flower thrips develop at temperatures above 50°F. At a temperature of 78°F to 82°F, the completed life-cycle from egg to adult is 12 to 14 days. As temperature decreases, time from egg to adult increases.

Green peach aphids can multiply in lower temperatures. A model has been designed for the development of green peach aphid, and we know that their development occurs when temperature is above 39°F and the rate of development increases until 89°F.

Twospotted spider mite development begins above 50°F. The optimum development temperature is between 85°F and 95°F, which explains why this pest is particularly a problem during warm weather and in hot greenhouses.

Greenhouse and silverleaf whitefly- - A model has been developed for the greenhouse whitefly, which states that development begins at a temperature above 47°F. Although the greenhouse whitefly and the silver leaf whitefly are different species, I believe the development temperatures are fairly close. There is a seven-day difference in time to development from egg to adult at 70°F in these two species.

The differences in the base temperature of each insect (the temperature at which development begins) enables us to determine the impact of lowering greenhouse temperature on insect populations. With a lower greenhouse temperature, insects with a lower base temperature would be impacted relatively less than insects with a higher base temperature. Therefore, populations of Western flower thrips and twospotted spider mites would increase at a slower pace at a lower greenhouse temperature compared to populations of green peach aphids. So, if you’re tempted to lower your greenhouse temperature, keep your eye out for aphids, as they will continue to develop relatively quickly compared to the other three insect pests.

Adapted from "How changing temperature influences greenhouse insect populations" by Jeanne Himmelein in the October, 2005 edition of the Greenhouse Alert Newsletter from Michigan State University.

Monday, October 27, 2008

Landscape - Abnormal Branch: Injury or Chimera?

A chimera is a genetic mutation that leads to a different appearance in part of a plant. This is often confused with some kind of damage or injury. Many of our variegated plants were originally found as chimeras from a branch or shoot of a non-variegated plant. The following is a short article on the subject.

Chimeras are botanical abnormalities that are often confused with nutritional or chemical disorders. “Chimera” is a term used to describe a single plant with two genetically different tissue types. Leaf variegation is the most common example of chimeras in plant species. The difference in foliage color and the banding of those colors are due to cell mutations in the meristematic tissue layers. Chimeras can be stable, in that the genetic differences are consistent and reproducible. These chimeras have spawned numerous of our variegated plant cultivars. Chimeras can also be unstable and unpredictable, surfacing sporadically on either shoots or individual leaves. The Bumald spireas are known for the sporadic appearance of unstable leaf chimeras. The stability of the chimera depends on the tissue layer where the mutation occurs. If you discover variegation on an individual stem and not over the entire plant, it is possible that it is a chimera and not an abiotic disorder related to plant nutrition or chemical injury.

Chimera on Anthony Waterer spirea.

Information and photo from a section of "Abiotic Plant Disorders - Symptoms, Signs and Solutions A Diagnostic Guide to Problem Solving" by Robert E. Schutzki and Bert Cregg, Departments of Horticulture and Forestry, Michigan State University Michigan State University. Go to for the full factsheet with photos.

Greenhouse - Growing Cooler Affects Media Temperature and Can Lead to Problems

Growing cooler can save on fuel costs in some greenhouse crops. However, it can also have some negative effects from having cooler media temperatures. The following is a good article on the subject from Michigan State University.

Don’t forget that cooler air temperatures can mean cool media temperatures. Media temperatures control nutrient and water uptake and can have a powerful effect on plant growth. This effect is most noticeable with plugs and small plants.

Optimum media temperature varies by type of plant and especially by plant age. Young plants require higher media temperatures than older, almost fully developed plants. Optimum temperatures are usually in the 60° to 65° range for most crops. Focus your efforts at providing optimum temperatures in the propagation/germination areas and early in the crop. As the crop matures, cool media temperatures will have less of an effect on plant growth.

Media temperature may be up to 10°F lower than air temperature with overhead heating systems when the plants are on benches. The difference between air and media temperature can be even greater when the plants are on the ground or have just been watered with cold water. The best way to determine media temperature is by using a media/soil thermometer. These thermometers are rugged and inexpensive but require calibration just as with thermostats and other temperature sensing equipment. Another way to check media temperature is by using an infrared thermometer. These units are more expensive but can measure temperatures from a distance, a useful feature when checking the middle of prop beds or hanging baskets. You should check them against a calibrated media/soil thermometer because the color of the media and/or pot can influence their readings.

Temperature gradients between air and media are caused by a number of reasons. Water evaporating from the media surface or the surface of the pot or plug tray cools the media especially in propagation or germination beds. With overhead heating systems warm air may be blocked before it reaches the media by the top of the plants or because the containers are placed on the ground or a solid bench surface. The ground is a huge heat sink and is very slow to warm up, especially in cloudy weather. Raising pots or flats just an inch or two off the ground or solid bench increases temperature significantly by preventing movement of heat to the cold ground/bench and increasing air movement around the roots.

Probably the greatest reason for cool media temperatures is watering with cold water. When the plant is young, the greatest component (by weight) of the media is water. Water absorbs a great deal of heat without changing temperature and the movement of energy (heat) from air to water isn’t very efficient. Since air doesn’t hold a great deal of energy (heat) per cubic foot you must circulate a lot of air around the pot/plug to increase media temperature. The most efficient way to increase media temperature is to water with tempered water. Seventy degree F water coming out of the end of the hose usually means the hot water heater is set at 100°F or slightly higher. Also consider reducing evaporation cooling by using bed covers or tenting instead of overhead misting in propagation beds.

Most of us are familiar with Phosphorus (P) deficiency symptoms (stunting, purpling of stems, leaf petioles and undersides of leaves) caused by cold media but low media temperatures also influence the uptake of water and all other nutrients. When the roots are not active because of low temperatures, water isn’t taken up and the plants can wilt even when the media has adequate water available. This is common when the sun suddenly comes out after a period of low light. Make sure your employees are trained to check media moisture levels rather than just react to the sight of wilted plants by watering. Calcium (Ca) moves with the water being transpired. If the root isn’t active, water isn’t moving into the plant and neither is Ca. Low temperatures also cause higher relative humidity around the plant which slows the transpiration of water, and therefore, the movement of Ca into growing points. Below 60°F media temperature Ammonium Nitrogen (NH4) is not converted into Nitrate Nitrogen (NO3-) by bacteria in the media. NH4 can build up to toxic levels if you don’t increase the percentage of NO3- in your fertilizer.

Lastly, the fastest way I know to kill roots is by drowning them. Cool media doesn’t dry out quickly and roots can be starved for oxygen for long periods of time. Make sure your media is highly aerated, with lots of large pores to allow water to drain and oxygen to penetrate. However, highly porous media doesn’t hold a lot of water so adjust your watering practices during warmer weather.

Reprinted from "Save fuel but don’t cause problems due to low media temperatures" by Dean M. Krauskopf, Southeast Michigan Greenhouse Educator, in the October 28, 2005 edition of the Greenhouse Alert newsletter from Michigan State University.

Sunday, October 26, 2008

Greenhouse - Easter Lily Forcing 2009

Greenhouse growers that do their own Easter Lily forcing should plan to receive bulbs soon if pot cooling and by early December if using pre-cooled bulbs. The following are some thoughts on scheduling this year's crop.

In 2009 Easter falls on April 12, this is mid-date Easter that will allow plenty of time for forcing. This is good news since you can grow cool for most of the schedule and still bring the crop in on time.

The normal Easter lily schedule for pot-cooled bulbs takes a total of 23 weeks. This includes 3 weeks in the pot at 60-62°F to stimulate root development, 6-weeks of bulb cooling at 40-45°F and then 14-weeks of greenhouse forcing at 60-65°F or higher as needed.

If doing your own cooling, for case-cooled bulbs the process is still 23 weeks but this includes 6-weeks bulb cooling at 40-45°F and then 17-weeks of greenhouse forcing.

If buying pre-cooled bulbs, you will want to obtain your pre-cooled bulbs for delivery in early to mid-December and pot them up around December 14th.

Reprinted in part from the current postings on the New England Greenhouse Update and the Maryland Greenhouse TPM/IPM weekly report.

Greenhouse and Nursery - Disinfectants/Disinfestants for Greenhouses and Propagation Houses

After fall production is done, take time to properly disinfect/disinfest your greenhouses. Propagation houses in nurseries should be disinfected/disinfested sometime between propagation cycles during the year. The following are some disinfectants for use in the greenhouse. Information is from the University of Massachusetts.

There are several different types of disinfectants that are currently used in the greenhouse for plant pathogen and algae control. They are quaternary ammonium compounds (Green-Shield®, Physan 20®, and Triathlon®), hydrogen dioxide (ZeroTol®, Oxidate®), chlorine dioxide (SelectrocideT) and chlorine bleach. Alcohol, although not used as a general disinfectant is mentioned here because it is used by growers to disinfect propagation tools. All these products have different properties. If possible, disinfectants should be used on a routine basis both as part of a pre-crop clean-up program and during the cropping cycle.

Organic growers have limited options for disinfectants. Oxidate® is the only material mentioned above that is currently listed by the Organic Material Review Institutes (OMRI), see . Ethyl or isopropyl alcohol is also allowed under the organic standards. Organic growers should always check with their certifying organization before using any material new to their farming practices.

Quaternary ammonium chloride salts (Green-Shield®, Physan 20® and Triathlon®).

Q-salt products, commonly used by growers are quite stable and work well when used according to label instructions. Q-salts are labeled for fungal, bacterial and viral plant pathogens, and algae. They can be applied to floors, walls, benches, tools, pots and flats as disinfectants. Physan 20® is also labeled for use on seeds, cut flowers and plants. Carefully read and follow label instructions. Recommendations may vary according to the intended use of the product. For example, the Green-Shield® label recommends that objects to be sanitized should be soaked for 10 minutes, and walkways for an hour or more. Instructions recommend that surfaces be air-dried after treatment except for cutting tools. The label recommends soaking cutting tools for 10 minutes before use, then using the wet tool on plants. One way to do this is by having two cutting tools, one pair to use while the other is soaking.

Q-salts are not protectants. They may eradicate certain pathogens, but will have little residual activity. Contact with any type of organic matter will inactivate them. Therefore, pre-clean objects to dislodge organic matter prior to application. Because it is difficult to tell when they become inactive, prepare fresh solutions frequently (twice a day if in constant use). The products tend to foam a bit when they are active. When foaming stops, it is a sign they are no longer effective. No rinsing with water is needed.

Hydrogen Dioxide (ZeroTol®, OxiDate®)

Hydrogen dioxide kills bacteria, fungus, algae and their spores immediately on contact. It is labeled as a disinfectant for use on greenhouse surfaces, equipment, benches, pots, trays and tools, and for use on plants. Label recommendations state that all surfaces should be wetted thoroughly before treatment. Several precautions are noted. Hydrogen dioxide has strong oxidizing action and should not be mixed with any other pesticides or fertilizers. When applied directly to plants, phytotoxicity may occur for some crops, especially if applied above labeled rates or if plants are under stress. Hydrogen dioxide can be applied through an irrigation system. As a concentrate it is corrosive and causes eye and skin damage or irritation. Carefully read and follow label precautions. Note that OxiDate® is the only product of the products mentioned in this article listed on the Organic Material Review Institutes (OMRI) website, in the newly-listed products section.

Sodium Carbonate Peroxyhydrate (GreenClean Granular Algaecide®, TerraCyte®)

Both algaecides are granular and activated with water. Upon activation, sodium carbonate peroxhydrate breaks down into sodium carbonate and hydrogen peroxide. GreenClean is labeled for managing algae in any non-food water or surfaces. TerraCyte in addition to being an algaecide is labeled to control moss, liverworts, slime, molds and their spores and is labeled for use on plants. Non-target plants suffer contact burn if undiluted granules are accidentally spilled on them.

Chlorine Dioxide (SelectrocideT)

Chlorine dioxide is a new disinfectant in the horticulture industry for controlling algae, bacteria, viruses, fungi and other microbial pests on greenhouse surfaces and in greenhouse irrigation systems. Currently it is labeled to be used to clean out irrigation lines with a periodic treatment at a moderate dose or to keep lines from becoming re-contaminated by treating irrigation water flowing through the system with a continuous ultra-low dose. Research continues to be conducted on this product to expand its use in the industry.

Chlorine bleach.

There are more stable products than bleach to use for disinfecting greenhouse surfaces. Chlorine bleach may be used for pots or flats, but is not approved for application to walls, benches or flooring. When used properly, chlorine is an effective disinfectant and has been used for many years by growers. A solution of chlorine bleach and water is short-lived and the half-life (time required for 50 percent reduction in strength) of a chlorine solution is only two hours. After two hours, only one-half as much chlorine is present as was present at first. After four hours, only one-fourth is there, and so on. To ensure the effectiveness of chlorine solutions, it should be prepared fresh just before each use. The concentration normally used is one part of household bleach (5.25 percent sodium hypochlorite) to nine parts of water, giving a final strength of 0.5 percent. Chlorine is corrosive. Repeated use of chlorine solutions may be harmful to plastics or metals. Objects to be sanitized with chlorine require 30 minutes of soaking and then should be rinsed with water. Some would say that rinsing is not necessary. Bleach should be used in a well-ventilated area. It should also be noted that bleach is phytotoxic to some plants, such as poinsettias.

Alcohol (70 percent) is a very effective sanitizer that acts almost immediately upon contact. It is not practical as a soaking material because of its flammability. However, it can be used as a dip or swipe treatment on knives or cutting tools. No rinsing with water is needed.

Disinfectants should be used on a routine basis both as part of a pre-crop clean up program and during the cropping cycle.

Reprinted from Cleaning and Disinfecting the Greenhouse by Tina Smith, Extension Educator, Floriculture Program, Dept. Plant, Soils and Insect Sciences, University of Massachusetts, Amherst.

Saturday, October 25, 2008

Nursery - Black Vine Weevil Active in Container Perennials

Black vine weevil is active this fall and is feeding on herbaceous nursery plant roots. The following is a good article on the subject from the University of Maryland.

Black Vine Weevils

Adult females notch the edges of the foliage in June through September. The larvae will continue to feed on the roots of herbaceous perennials until late fall when they will migrate down to the bottom of container grown plants. Susceptible hosts include: Astilbe, heuchera, hosta, sedum, bergenia, aster, lily of the valley, foam flower, epimedium, fern, cranesbill geranium, heather, liriope, peony, phlox, and toad lily.

Black Vine Weevil damage to roots.

Black Vine Weevil

Chemical Control: Bifenthrin (Talstar) applied as a soil drench will control larvae.

Biological Control: Several species of entomopathogenic nematodes applied as a soil drench are effective including; Steinernema carpocapsae, S. glaseri, and Heterorhabditis bacteriospora (= heliothidis). In Europe, Heterorhabditis megidis has also been used successfully to control black vine weevil larvae. The nematodes will reproduce inside the black vine Black Vine Weevil Damage weevil larvae, and then migrate out into the soil to look for another host. For nematode survival, the soil must be kept moist and soil temperatures must be above 10° C (50° F). Steinernema kraussei has been used to control black vine weevil at temperatures between 43-50° F. This species may be a good choice for growers at this time in the fall.

Adapted from an article in the October 24, 2008 edition of the TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers from the University of Maryland Cooperative Extension.

Greenhouse and Nursery - Cleaning and Reusing Pots and Flats

With the cost of production increasing dramatically over the past 3 years, greenhouse and nursery producers may be considering reusing pots and flats. It is very important that you disinfest pots before you reuse them. The following is a good article on the subject.

Cleaning and re-using pots, trays and flats may be an economical move for some growers, but it is important to do it right. Plant pathogens like Pythium, Rhizoctonia and Thielaviopsis can persist in root debris or soil particles on greenhouse surfaces. If you know the previous crop had a disease problem, it is a safe move to avoid re-using those containers. It is also a good idea to avoid planting crops that are prone to Thielaviopsis problems, like pansies, in containers that have been previously used.

Even if there was no evidence of disease in the crop, all containers should be washed thoroughly to remove all soil particles and plant debris before being treated with a greenhouse disinfectant – organic matter can protect pathogen spores from coming in contact with the disinfectant solution. There are several products available for disinfecting greenhouse surfaces: quaternary ammonium products (Greenshield®, Physan 20™, Triathlon®), and hydrogen dioxide (ZeroTol®, OxiDate®). Follow label directions for these products - labels indicate that pots must be soaked for at least 10 minutes in these products to be fully effective. A 10 percent solution of household chlorine bleach (one part bleach to 9 parts of water) may be used for pots and flats, but the solution has a shorter activity period than other disinfectants, losing half its strength in 2 hours. Sanitation with chlorine bleach also requires a longer soaking time. Chlorine bleach is also phytotoxic to some plants, and must be used in a well-ventilated area to protect workers.

Tina Smith from the University of Massachusetts has an excellent fact sheet called “Cleaning and Disinfecting the Greenhouse” that describes the greenhouse disinfectants and their proper use in great detail, including links to labels of disinfecting products. The fact sheet can be found at:

Reprinted from the October 24, 2008 edition of the Greenhouse TPM/IPM Weekly Report from the University of Maryland Cooperative Extension, Central Maryland Research and Education Center.

Friday, October 24, 2008

Landscape - Fall Sanitation

Fall is the time to practice sanitation in landscapes to reduce disease pressure next year. Collected plant material should be composted. The following is a short article on the subject.

Fall cleanup is an important fall chore. Be sure to compost infected fallen leaves that may harbor plant pathogens. Most fungi that are parasites do not complete well with the decay fungi (saprophytes) in compost piles and decline in numbers relative to the decay fungi. Composted leaves are not likely to harbor plant pathogenic fungi that infect leaves especially if the pile heats to 180° F. There are exceptions. Do not compost any plant material that died from Verticillium wilt, Fusarium wilt, Southern blight (Sclerotium), Sclerotina white mold, or black root rot (Thielaviopsis).

Bob Mulrooney, Extension Plant Pathologist, UD

Turf - Know Your Herbicides III

This is the third in a series of posts on knowing those herbicides that are used on turf. This post is on those products containing fluroxypyr. Click on slides for a larger image.

Momentum FX2 weed control spectrum.

Momentum FX2 weed control spectrum.

Information from the labels and also from a presentation by Dr. Tony Koski, Colorado State University Extension.

For labels go to these sites:

Thursday, October 23, 2008

Landscape and Nursery - Horticultural Oils

Horticultural oil is a major tool that is used for the control of scales, aphids, mealybugs, and other similar piercing/sucking insects in nurseries and landscapes. The following is an article on the subject.

HORTICULTURAL SPRAY OILS are great tools to use in the fight against pests and diseases. With the “dormant” season fast approaching, the subject of spray oils is an important one to review. A “dormant” oil is one that should only be applied while plants are in their dormant phase. Many evergreen plants are not dormant during the fall, winter, and spring and can be severely injured by dormant oils. In contrast, “horticultural” oils (also called summer or verdant oils) were developed to be used when plants were not in the dormant phase. Most horticultural spray oils are used at rates as low as 1% by volume (1.28 fl. oz./gal water) or 2% by volume (2.56 fl. oz./gal water). However, they can be used at dormant rates (3-4% by volume), depending on the application site. Oils are mixed with emulsifiers to allow the oil to mix better in water. Since oil and water do not thoroughly mix even with the best emulsifiers, keep the solution agitated to avoid spray burn. Other key terms to know when selecting a spray oil are the UR Number the amount of unsulfonated residues - these residues are what contribute to spray burn. A UR number/percent of 92-96 is a good value. Another value to note is the “distillation range” of your oil a value in between 412F-468F is a higher quality spray oil with less impurities. Don't apply spray oils below freezing or when humidity is high. Always avoid using them on plants with a grayish cast or waxy coat (e.g. Colorado Blue Spruce). While oil may be tank mixed with some pesticides, this increases chances of spray burn particularly if the tank mixed product is an EC formulation. NEVER TANK MIX OIL WITH SULFUR this is an unsafe and dangerous practice for plants and people. A great web resource for horticultural oils can be found at a Cornell Cooperative Extension Website:

Note: The good thing to know is that most horticultural oils now on the market that are sold by reputable suppliers are very highly refined and meet the standards above. - Gordon Johnson

Article by Casey Sclar, IPM Coordinator, Longwood Gardens

Turf - Know Your Herbicides II

This is the second in a series on knowing the herbicides that are used in professional turf management. The second post is on the material carfentrazone.

List of weeds controlled. Quicksilver is also effective on controlling moss in turf.

One of the combination products containing carfentrazone.

Another of the combination products containing carfentrazone.

Information from the Quicksilver label and also from a presentation by Dr. Tony Koski
Colorado State University Extension. For labels go to these sites:,,

Wednesday, October 22, 2008

Landscape - First Significant Fall Frost Across Mid State on Monday Night

The first significant fall frost occurred across parts of midstate on Monday morning. The frost was heavy enough to affect many annual flowers, some perennials, and a smaller number of trees and shrubs. The following are the lows on Monday morning, October 20, 2008 (in degrees F):

Harrington 30.1
Smyrna 30.5
Blackbird 30.5
Dover 28.8
Viola 27.9
Sandtown 28.6
Ellendale 31.9

Dieback in annual vinca from the frost. Note the winter annual broadleaf weeds in the background that were not affected. They will not go cold dormant until a heavy freeze. Click on picture for a larger image.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

Turf - Know Your Herbicides I

This is the first in a series on knowing the herbicides that are used in professional turf management. The first post is on the material quinclorac.

Information largely from the Drive label. Go to for the full label.

Tuesday, October 21, 2008

Business - Adding Firewood as an Enterprise

In these tough economic times, horticultural businesses are looking for ways to add to add income. One potential business is firewood. If you have access to a woodlot or add woodlot management services to your business, you may be able to get into a firewood enterprise. The following is more information on heating with firewood.

The heating season is upon us and many families and businesses will be looking for ways to save money on heating costs. The following is information on the cost of different sources for heating a house for the heating season and savings burning wood.


The burning of firewood or wood pellets in a stove for heat has gained great interest as fossil fuel prices have escalated. It takes an investment to purchase a stove and properly install and operate it, but the savings can be substantial. Heating value of any fuel is measured in British Thermal Units (Btu). One Btu is the amount of energy required to raise a pound of water 1 degree Fahrenheit. Different types of heaters burn fuel at different efficiencies. For example, the average efficiency of an airtight wood stove is around 50%, but oil and gas burners may be 65‐80%. Comparison of the cost of various heating fuels can be made on the basis of their heat equivalents as expressed in dollars per million BTU ($/MBtu). Assuming it takes about 60 million Btu’s to heat a home for the winter, your total heat bill can be estimated. The table provides the heat cost comparisons using current regional prices of various fuels. The cost to heat for the winter ranges from a high of $1836 for an air source heat pump to $409 using firewood at $150 a cord. Wood pellets are still costly at $909. You can see that by burning firewood, your winter heating costs can be dramatically reduced.

To calculate your heating costs try the U.S. Dept of Energy fuel calculator:

For more information on producing firewood from your woodlot, go to:

Adapted from the Fall 2008 edition of the Branching Out newsletter from the University of Maryland.

Landscape - Invasive Species Resources

The USDA has released an updated version of their field guide of invasive plants of forests and woodlands. Those who manage lands with invasive plants should add this guide to their reference collection. The following is a link to the guide on the internet and information on how to order.

UDSA Forest Service Northeastern Research Station, Eastern Region, Northeastern Area State & Private Forestry

Invasive Plants Field and Reference Guide: An Ecological Perspective of Plant Invaders of Forests and Woodlands

Web links:

The USDA Forest Service has issued an updated “Invasive Plants Field and Reference Guide: An
Ecological Perspective of Plant Invaders of Forests and Woodlands.” For a copy, contact Rod Whiteman, USDA Invasive Species Coordinator, at 304‐285‐1555 or

Also go to for more information on invasive species and for invasive species information in the eastern region.

UD Plants for a Liveable Delaware

Monday, October 20, 2008

Business - Survival in an Economic Downturn IV: Focus on Customer Service

This is a continuation of the series on survival of horticultural businesses in an economic downturn. This post is devoted entirely to the need to focus on customer service in a tight business environment.

Customer service should be a focus in bad economic times. It is a vital component in retaining customers. Some points to consider:
  • Keep in contact with current customers on a regular basis. Ask about their needs and how you can provide better service.
  • Have good follow-up. Resolve any issues in a timely manner.
  • Good communication is a key. Provide clear information to your clients, be truthful, educate clients about your business and its products and services, and provide detailed information about services or products when asked. Most client loss is due to poor communication.
  • Improve your communication skills with classes or by practicing with other professionals.
  • Timeliness is an important part of customer service. Be available for customers and. respond to concerns, questions, orders, or requests promptly. Focus on prompt service. Be responsive to requests.
  • Offer a range of products and services to meet clients needs.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

Greenhouse - Effects on Crops When Considering Growing at Lower Temperatures II

Although prices have dropped recently, continued high energy prices are prompting many greenhouse growers to consider lowering their greenhouse temperature setpoints to reduce their monthly heating costs. This is the second post on the subject taken from an article from the Michigan State University Greenhouse Alert Newsletter.

Cold-tolerant and cold-sensitive crops

The reason for the difference in how temperature influences crop timing is related to the base temperature of a plant. Plants with a low base temperature can be considered “cold-tolerant plants.” Those with a high base temperature can be called “cold-sensitive plants.” Cold-sensitive plants are more sensitive to a lower greenhouse temperature than cold-tolerant species. There are also plants that fall between these categories (base temperature between 39°F and 46°F), such as red salvia. All plants respond to temperature during all stages of development. For example, seedlings of Salvia ‘Vista Red’ grew faster as temperature increased from 57 to 79°F (14 to 26°C). At these temperatures, plugs grown in 288-cell trays took approximately 6.5 weeks to finish at 57°F and about four weeks at 79°F. Plants also respond to temperature during the finish stage. For example, under the low light conditions of winter, time from transplant to first flowering of Salvia ‘Vista Red’ took 12 days longer at 63°F than at 73°F.

Temperature effects on plant quality

For many crops, plant quality at the same stage of development increases as growing temperature decreases. If plants are grown at similar light intensities but at different temperatures, marketable plants grown at cooler temperatures often have thicker stems, greater branching, more roots, and more, larger flowers. Exceptions to this are plants that grow best in warm conditions, such as hibiscus. Therefore, one of the benefits of growing at cool temperatures is that overall plant quality could be improved even though crop timing is delayed. However, remember that some plants, especially warm-season plants, can experience chilling injury at cool temperatures

Adapted from "Temperature effects on crop timing and plant quality" by Erik Runkle,Horticulture, in the October 28, 2005 edition of the Michigan State University Greenhouse Alert Newsletter.

Sunday, October 19, 2008

Business - Effects of the Economic Downturn on Horticultural Businesses and How to React

The economic downturn starting with the housing bust has had a large impact on horticultural businesses. The following are some of the effects and how to react from a business standpoint.
  • Situation: Sod farms and turf companies that install sod have seen a large drop in business as there has been a large slowdown in new construction projects. Initially there was business to be had in completing existing projects. As existing projects are completed, there are few new project to take their place.
  • Reaction: downsizing makes the most economic sense in this situation. Sod farms will carry inventory much longer and will have land rent, irrigation, and turf maintenance costs that are associated with this carry over so new plantings should be delayed. Installation firms will have to cut back employees. Search for sales in those areas that are not depressed as much such as sports field installations. Switch part of production areas to different species for specialty installations such as Bermudagrass.
  • Situation: Nurseries and landscape installation companies have also seen the same effect in slower business due to reduced construction and limited demand for new installations.
  • Reaction: Landscape installation companies should alter business models to focus more on customers that are renovating landscapes or adding to landscapes. Nurseries should focus more on newer plant introductions for these renovations as customers are often looking for the new and unique. Consider where work is continuing and the plant needs for those uses. Required restoration projects might be an example. Consider producing more for consumer sales where there may be less of a drop off in sales (more people doing their own landscaping). Nursery inventories will have to be maintained for longer periods with associated costs such as potting up to a larger size for container nurseries. Reduced planting of new inventory may be necessary or reducing prices on existing inventory may be necessary to eliminate the maintenance costs. Landscape firms may have to sell more design services and less installation services, especially to lower end customers that may move toward doing self-installations.
  • Situation: Greenhouses are experiencing higher production costs and therefore have to pass those costs along to customers. As a result, we have seen reduced demand for the first time in many decades. In the past, we have thought that greenhousew sales are recession-proof because sales will be boosted by consumers staying more at home and gardening more. We may have reached a breaking point where this no longer is the case.
  • Reaction: Downsizing production may be necessary to better match demand. Unsold inventory can eat dramatically into profits. Pay close attention to customer service to keep existing customers buying. Offer later season discounts to loyal customers to keep inventory moving.
  • Situation: Lawn care and landscape maintenance companies will be affected less by the bad economy. However, some clients may switch to doing their own maintenance or lawn care as they belt-tighten.
  • Reaction: Do everything you can to retain current customers, especially good ones. Intensify customer service activities. Communicate with clients more often and ask about needs. Offer lower cost maintenance packages as an alternative to keep good clients. You may have to drop some clients that are marginal and reduce work forces. Pay special attention to the needs of business and corporate clients and larger accounts.

Gordon Johnson, Extension Horticultural Agent, UD, Kent County

Greenhouse - Effects on Crops When Considering Growing at Lower Temperatures I

Although prices have dropped recently, continued high energy prices are prompting many greenhouse growers to consider lowering their greenhouse temperature setpoints to reduce their monthly heating costs. This is the first post on the subject taken from an article from the Michigan State University Greenhouse Alert Newsletter.

Temperature influences crop timing, plant quality and energy consumption, as well as other issues. When determining a growing temperature, it is important to understand how temperature influences plant growth and development so that growers can optimize their production schedules and still produce high quality plants on time.

Temperature controls crop timing

Within the temperature range of most greenhouses during the winter, plants develop leaves and flowers progressively faster and faster as temperature increases. Thus, turning down the thermostat during the day or night will delay crop timing. In other words, if you grow plants at cooler-than-normal temperatures, production time will increase. This means that, to finish a crop on the same time as last year, you must begin growing the crop earlier in the year at the cooler temperature compared to the date you would need to start your crop at a warmer temperature.

Plants respond differently to temperature

As temperature decreases, there is some temperature at which a plant ceases to develop. This temperature is called the base temperature, and varies from crop to crop. For example, the base temperature for seed petunia is about 39°F (4°C), which means that at or below this temperature, petunias stop growing. For seed vinca (Catharanthus), the base temperature is much higher, around 50°F (10°C). Vinca placed in a 45°F (7.5°C) greenhouse will not develop leaves or flowers, but a petunia will continue to grow (just slowly).

As temperature increases above the base temperature, plants grow faster and faster. Figure 1 illustrates the time it takes for petunia and vinca plants to flower at various temperatures. As temperature increases above the base temperature, a small increase in temperature can make a big difference in the time to flower. As we get to warmer temperatures, the same increase in temperature has a smaller effect on accelerating flowering.

Lowering the temperature by 5 degrees has a somewhat small effect at warm temperatures, and has a larger effect at cooler temperatures. The effect of lowering the temperature also depends on the crop. For example, lowering the temperature from 65 to 60°F would take petunia about 13 days longer to flower, and would take vinca about 30 days longer to flower.

Adapted from "Temperature effects on crop timing and plant quality" by Erik Runkle,
Horticulture, in the October 28, 2005 edition of the Michigan State University Greenhouse Alert Newsletter.

Saturday, October 18, 2008

Greenhouse and Interiorscape - Mealybugs

Mealybugs can be a problem on longer term greenhouse crops and interiorscapes. The following is an article on the subject from the New England Greenhouse Update.

Mealybugs are typically a problem on long-term crops such as orchids, foliage plants that are often found in retail greenhouses, conservatories, and interiorscapes. Common species include the citrus mealybug (Planococcus citri), longtailed mealybug (Pseudococcus longispinus), and obscure mealybug (Pseudococcus viburni). Other mealybugs that have been introduced into the USA, which may be present in greenhouses, include the pink hibiscus mealybug (Maconellicoccus hirsutus), maderia mealybug (Phenacoccus madeirensi), and the Mexican mealybug (Phenacoccus gossypii).

Longtail mealybug. Photo from David Cappaert, Michigan State University,

Mealybugs usually enter a greenhouse on already infested plant material. Now is a good time to inspect any tropical plants that you are thinking of overwintering in your greenhouses. Look on leaf undersides, petiole and leaf junctions, and near the base of plants. Mealybugs can also be found on the inside of container lips and in the drainage holes of containers. On standard plants, they may hide under the tape on the garden stakes. Mealybugs can live for 2 to 3 weeks without hosts. Power washing the greenhouse between crops is helpful to remove mealybugs hiding in cracks and crevices. Young, immature mealybugs prefer to move to tip growth to feed, so inspect stock plants before taking cuttings. Susceptible plants, should be monitored closely and include coleus, rosemary, sage, Swedish ivy, artemesia, Ipomoea, and gardenia.

Chemical control is difficult because the mealybug’s waxy covering reduces its contact with spray materials. Crawlers, with the least wax, are most susceptible to chemical treatments. The systemic insecticide, Safari, is very water soluble and effective against mealybugs as a drench treatment. Recent research has also shown that Celero, Aria & Talus or Talus also work well. Repeated applications may be needed as eggs hatch throughout the growing season.

Stanton Gill, University of Maryland reports that growers of edible herb crops may apply insecticidal soap (containing fatty acid and alcohol) to dissolve some of the waxy coating, then follow-up with an application of horticultural oil a day later.

Biological Control of Mealybug

To choose the best natural enemy, it is important to have the mealybug identified to species. For example, the commercially available parasitoid, Leptomastix dactylopii only attacks the citrus mealybug. In general, predators are less efficacious against mealybugs than parasitoids. The mealybug destroyer, (Cryptolaemus montrouzieri) feeds on citrus and longtailed mealybugs as adults and larvae. .The wax-covered larvae resemble mealybugs, except they are twice as large and feed on mealybug eggs, crawlers, and honeydew. Adults and young larvae prefer to feed on mealybug eggs, however older larvae will attack any stage. The mealybug destroyer is also most effective during spring through fall; less so during winter.

Reprinted from a posting by Leanne Pundt, University of Connecticut and Tina Smith, University of Massachusetts on October 9, 2008 on the New England Greenhouse Update website

Business - Survival in an Economic Downturn III

This is a continuation of the series on business survival in an economic downturn. This post will focus on renegotiating contracts, jobs, or service agreements to keep customers, picking up customers from other companies/operators that decided to go out of business, and finding new customers when potential clients are holding tight to their money.

One aspect of survival in an economic downturn is the need to maintain your customer base and to find new customers (to replace lost clients or to grow the business with new clients). The following are some thoughts:
  • Consider renegotiating contracts, jobs, service agreements, or purchase agreements to keep your customers. For lawn and landscape maintenance companies, you may need to reduce the cost to customers by offering a reduced service package. For horticultural production businesses such as greenhouses and nurseries, you will likely have to contend with reduced orders. This means you may have to reduce your minimums or extend quantity discounts to lower amounts to keep customers. For landscape installation companies, you may have to scale back jobs to better fit clients budgets in tight economic times.
  • Replacing lost customers will become more of a challenge in tight economic times. Although it is unfortunate that some companies will decide to go out of business, it does provide an opportunity to pick up clients by purchasing their customer list, taking over their service contracts, bidding for their jobs, or filling their orders.
  • Finding new customers in an economic downturn is even more of a challenge. As mentioned above, you can look for new clients when other companies go out of business. You may need to change your business model to consider clients that you have not targeted before. Examples: a wholesale nursery or greenhouse can open up a retail yard, open their business to retail sales in certain time periods, hold plant auctions periodically, or target sales to smaller landscape firms with reduced minimum purchases. A landscape firm that targets higher income customers may open a division that services lower income customers.
  • Reducing prices may increase demand to some degree and thus will pick up new customers. This is dangerous as margins in many businesses are already tight. When reducing prices consider that it will be hard to increase them in the future without losing customers. You must do a thorough economic analysis to see what impact reducing prices will have on your bottom line. Consider any cost cutting measures or increased efficiencies that will allow you to reduce prices without impacting profits.
  • Make customer service a priority. By providing superior service and better attending to the needs and wants of clients, you can often maintain that customer even through down times.
  • Maintain contact with past customers even if they left for another lower cost firm or just decided to do without. You may pick them up again when the economy turns around.
  • Expand relationships with existing clients. Offer your best clients even more services. Negotiate long term deals with these clients to offer your company more stability.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

Friday, October 17, 2008

Landscape - Planting Too Deep and Too Shallow

The two most common problems in landscapes that we see are planting too deep and too shallow. The following is a short article on the subject.

When planting, look for the root flare, and plant the ball with the root flare level with the ground. If you plant too deep or too shallow plants will often fail in the landscape.

When examining a tree or shrub that has been planted too deep, be careful when uncovering roots. These plants often have been buried for several years and many roots have developed near the surface. These roots can be killed when uncovered. Adjusting planting depth is best done in spring after the weather settles to allow time for new root growth to develop and to allow the plant to adjust. Avoid doing this in the fall. Often it will be impossible to reset the tree or shrub without doing extensive damage to root systems.

Symptoms associated with planting too deep include wilting, stunted growth, chlorosis, dieback, early fall color, scorch and the development of adventitious roots off of trunks. Planting too deep restricts the amount of water and oxygen to the fine root systems, lowering the trees vitality. Trees planted too deep are also more subject to canker development and wind throw.

Planting too shallow can also be problematic. It can result in roots drying out, root death, and the plants being prone to water stress. Plant will be more shallow rooted and have reduced rooting leading to toppling in heavy winds and storms.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County. Some information from the Michigan State University Landscape Alert Newsletter.

Turf - Benefits of Earthwoms

Earthworm activity in the turf areas is a sign that your soil is healthy. The following are some benefits of earthworms in turf.

In most turfgrass situations, the benefits of earthworm activity by far outweigh any negative effects. Earthworms play a vital role in the development of soil structure, fertility, and nutrient recycling. They ingest organic matter along with soil and excrete the mixture of digested organic matter and soil as castings. These casts modify soil structure by breaking down larger structural units into finer, spherical granules, and in some soils, can contribute up to 50% of the soil aggregates. Many earthworm species deposit their casts beneath the soil surface into voids and thus contribute to soil structure development. In contrast, species that build permanent, vertical burrows deposit their casts on the soil surface and contribute more to soil profile development. In some soils earthworm casting deposition on the soil surface can be equivalent to a ¼” deep uniform layer of enriched topsoil per year. Earthworms also improve the nutrient availability in soil through the digestion and liberation of nutrients and their mixing with soil and redistribution in the soil through cast deposition. The burrowing activity of earthworm improves soil aeration and drainage of excessive water and reduces soil compaction. Up to 66% of all pore space in some soils is estimated to be the result of earthworm burrowing. In turfgrass, earthworms are the major contributors to the breakdown of thatch. By feeding on decaying thatch and leaf litter they mix it with soil and stimulate its microbial decomposition. They also incorporate large amounts of soil into the thatch layer and thus improve its suitability for turfgrass growth. Thatch is rarely excessive where earthworms are abundant.

Reprinted from "Earthworms in Turfgrass" by Albrecht M. Koppenhöfer, Ph.D., Turfgrass
Entomology and James A. Murphy, Ph.D., Turfgrass Management in the October 7, 2004 edition of the Plant and Pest Advisory, Landscape, Nursery and Turf Edition from Rutgers University

Thursday, October 16, 2008

Landscape and Nursery - Boxwood Leafminer

Watch for boxwood leafminer activity this time of year. The following is a short article on the subject from Rutgers University.

BOXWOOD LEAFMINER: This particular host specific pest is a good example of why it can still be important to monitor plants during the off-season. Although the single generation leafminer larvae have been in boxwoods leaves since May, their presence in new foliage is often not readily apparent until the fall. Most of the activity and feeding damage by the fly larvae are done during the fall and winter. Blister-like blotch mines are now just becoming noticeable on current season infested leaves. While most insect pests are winding down for the year, the boxwood leafminer is just heating up. When symptoms suggest their presence, “break the back” of the leaf and peal away the lower epidermis to detect the still clear and thin larvae (usually several are found in each leaf). As feeding continues through the fall months, the larvae develop into larger, yellow colored maggots. After a mid-winter resting stage the larvae begin feeding again in late winter. With heavy infestations, defoliation can occur in the spring. The various neonicotinoid class root systemics should provide outstanding, long lasting results against this pest. As long as good root uptake of the material is achieved, success is usually assured. Within a week, sufficiently lethal insecticide levels should be translocated up into the boxwood foliage if healthy roots and adequate soil moisture are present.

Blotch on boxwood leaf opened up to reveal the boxwood leafminer larvae. Photo from Clemson University - USDA Cooperative Extension Slide Series,

Reprinted from "Landscape IPM Pest Notes" by Steven K. Rettke, Ornamental IPM Program Associate in the October 7, 2007 Edition of the Plant and Pest Adivsory, Landscape, Nursery and Turf Edition from Rutgers University.

Landscape - Twig Drop in Oak

If you are called by a client to investigate twig drop in oaks this time of year, there are two common causes. The following is an article on the subject from Rutgers University.

Observations during the fall season may show numerous fallen twig branches on the ground beneath a client’s favorite large oak tree. Usually the twigs are not much more than ¼ inches in diameter and the leaves are still attached. Two possible causes for the fallen twigs are from activity by gray squirrels or by an infestation of twig pruners (roundheaded beetle borers). Gray squirrels are notorious in the fall season for “attacking” oaks and other large trees during the weeks prior to leaf drop. They litter the ground beneath trees with twigs less than ¼ inch in diameter after chewing them off and letting them drop to the ground. When examining the end of the twig, look for the characteristic bevel or slant cut chewed by the squirrel. A couple of possible reasons for this squirrel behavior are to get acorns to the ground and to use the twigs and leaves for nesting materials.

Twig pruners are native longhorned beetles and are often found feeding on open grown oaks and other deciduous shade trees. The larval stages that feed within the twigs and small stems are called roundheaded borers. The larvae of this single generation borer will feed and grow in the twigs during the summer months. However, by late summer most of their feeding damage has been sufficient to girdle and weaken the twigs. Winds that are strong enough can then cause twigs to snap and fall to the ground with the larvae still inside. If an accumulation of fallen twigs becomes apparent in August and into September, then they should be examined for the possible presence of this borer. The broken ends will have a concave cut and the white larvae can be observed by cutting lengthwise at twig ends. The twig pruner overwinters as pupae within the fallen twigs/stems and emerges as longhorned beetle adults the following year in May/June. This minor pest can successfully be controlled with sanitation cleanup during the fall months. The use of insecticide sprays is not needed or recommended.

Reprinted from "Landscape IPM Pest Notes" by Steven K. Rettke, Ornamental IPM Program Associate in the October 7, 2007 Edition of the Plant and Pest Adivsory, Landscape, Nursery and Turf Edition from Rutgers University.

Wednesday, October 15, 2008

Landscape - Perennial Flower Garden

I was recently asked for suggestions for a perennial flower garden with long blooming plants in late spring, summer, and fall up to frost. While it is too late to plant perennials now, you can plan and place plant orders for the spring. One option is to use landscape plugs. These are much more cost effective than plants in quarts or gallons when landscaping a large area or doing mass plantings. Many perennials will establish quickly from landscape plugs and will bloom the same year. The following is the list I gave the client:

Achillea - any of the long blooming yarrows (many to choose from in many colors)
Agastache rupestris
Echinacea - any of the cone flowers (many to choose from in several colors)
Eupatorium dubium 'Little Joe'
Eupatorium maculatum 'Bartered Bride'
Gaillardia 'Fanfare'
Gaura - any of the Gaura varieties (many to choose from in several colors)
Helenium - any of the Helenium varieties (many to choose from in several colors)
Heliopsis helianthoides 'Ballerina'
Hibiscus - any of the Hibiscus varieties (many to choose from in several colors)
Kalimeris integrifolia 'Daisy Mae'
Nepeta subsessilis - Showy Catmint
Perovskia 'Little Spire' Russian Sage
Rudbeckia - any of the black eyed susan varieties
Salvia verticillata 'Purple Rain'
Scabiosa 'Pink Mist'
Verbena 'Homestead Purple'

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

Tuesday, October 14, 2008

Nursery, Greenhouse, and Landscape - Powdery Mildew Control Starts With Plant Selection

We had a bad powdery mildew year in 2008. Powdery mildew control starts with plant selection. Choose plants that are not susceptible to powdery mildew or those varieties that have been bred or selected for powdery mildew resistance. The following is a list of plants where powdery mildew is common.

Some of the more common hosts of powdery mildews include: apple and crabapple, azalea and rhododendron, ash, basswood, beech, Berberis, birch, blueberry, buckeye, catalpa, Chinese photinia, chrysanthemum, cotoneaster, crape myrtle, dahlia, delphinium, elm, eucalyptus, euonymus, flowering dogwood, gardenia, hawthorn, holly, honeysuckle, horse chestnut, hydrangea snowball, kalanchoe, Kalmia, leucothoe, ligustrum, lilac, Lonicera, lilac, magnolia, maple, monarda, oak, phlox, Prunus (peach, plum, cherry, apricot), pear, peony, poplar, privet, pyracantha, Reiger begonia, roses, serviceberry, spirea, smoke-tree, snapdragon, sycamore, tulip tree, Vaccinium, viburnum, walnut, wintercreeper, willow, wisteria, and zinnia.

Information from the Plant and Pest Advisory from Rutgers University

Greenhouse - Banker Pepper Plants and Pirate Bugs for Thrips Control

Using banker plants to attact thrips and then using thrips predators to control them is a technique that is being used in some greenhouses as an alternative to chemicals and where insectide resistance has developed in thrips populations. The following is information on using minute pirate bugs for thrips control.

A biological control technique for thrips control in the greenhouse involves releasing the predaceous minute pirate bug, Orius insidious, on dwarf pepper plants like ‘Black Pearl’. One pepper plant covers around 1,000 ft2 of growing area. Plant them in 6” pots in November or early December. The plants need to be growing for about 2 months before you start your spring bedding plants. With high energy costs this may be later than normal in 2009, so once you establish a start date for your spring crop then determine the when to get the pepper plants started. Release 60 - 80 minute pirate bugs per pepper plant. ‘Black Pearl’ Pepper They will lay eggs in the same area where thrips lay eggs, usually in or near flowers. Pepper plants are magnets for thrips, and serve as banker plants and indicator plants for early detection. As long as the pepper plants are in flower and producing pollen, the minute pirate bugs will reproduce on the banker plants. The adults will fan out across the greenhouse and kill 1st and 2nd instar thrips larvae and adult thrips. The good news is that only one release of minute pirate bugs onto the banker plants is necessary. To give you an idea of cost, 500 minute pirate bugs would be around $50 - $60.

Information from the October 10, 2008 edition of the Greenhouse TPM/IPM Weekly Report from the University of Maryland Cooperative Extension, Central Maryland Research and Education Center.

Monday, October 13, 2008

Business - Buying an Existing Business

With the economic downturn some horticultural business will decide to sell or liquidate. There may be opportunities to get into a horticultural business or to expand your business buying another existing business. The following are some considerations and cautions in buying an existing business.
  • Develop your plan for this new business. Does this business match your personal and financial objectives? What do you expect from this business? What are you willing to risk and how much time can you devote to learning and running the business?
  • If using the business to expand your customer base or production what will be the impact of adding the business. Will you be able manage the additional employees, production facilites, customer base, or employees? Will the addition of the business add to your bottom line? Do a complete cash flow projection and financial analysis before moving forward with the purchase.
  • Go visit the business seller. Ask to see the financial statements, a list of customers, prices, ask the reason for selling, and check the existing inventory.
  • Review facilities and equipment closely. Is the equipment in good shape or will considerable capital investment be needed to keep the business running?
  • Are there any legal actions pending against the present operation and are there any
    business leases or mortgages on any properties involved?
  • If an agreement is reached, have an attorney draw up the sales agreement and
    research state records for any liens on the property for failure to pay debts.
  • Before signing a sales contract, the seller should present a final count of assets,
    including inventory.

Purchasing a business is an exciting and challenging undertaking. But, carefully analyze exactly what it is you’re buying. No one wants to buy someone else’s business problems.

Adapted in part from "Buying an Existing Business – Look Before You Leap" in the Fall, 2008 Edition of the Mastering Marketing newsletter from the University of Maryland Cooperative Extension.

Greenhouse and Nursery - Environmental Horticulture Resources at the University of Maryland

The following are links to information for nursery and greenhouse growers from the evironmental horticulture program at the University of Maryland. In particular, there is information on fertilizer requirements for many horticultural plants.

Environmental Horticulture refers to the use of greenhouse and nursery plants to improve aesthetics in the human environment.

Over the past several years, we have performed a series of research trials studying fertilizer requirements for a wide variety of herbs and ornamental plants. In addition, we provide a large amount of information in the form of fact sheets designed to be useful for both industry professionals and the general public. Included below is a summary of our research results as well as an index of the fact sheets we have available, including a series covering general production information and a series highlighting production and consumer care factors for a variety of selected plant species:

Tom Blessington 12005 Homewood Road Ellicott City, MD 21042 (410) 531-6947

Research Data
Summary of Previous Results
Current Results
General Information Fact Sheets
Greenhouse Management and Operations
General Production Information
Selected Plant Species - Production and Consumer Care Fact Sheets
Perennials (A-G)
Perennials (H-Z)
Ornamental Grasses

Sunday, October 12, 2008

Landscape - Dieback in Needled Evergreens I

I recently had a question from a landscaper about dieback in evergreens. This year we are again seeing the loss of many evergreens. The following is the first posting on the subject using material from the Ohio State University.

Each year various narrow-leafed evergreens such as pines, Taxus and spruce are affected with needle yellowing and browning, dieback, poor vigor or death. These are problems often associated with one or more environmental stress factors. An explanation of some of these stress factors follows.

Wet Soil

Excessive amounts of water can result in a saturated soil, reducing oxygen levels to a point where small roots weaken or die. This root decline can be sudden or gradual and the roots may be invaded by various soil-borne fungi. Continuous wet conditions lead to progressively worse situations. If the top of the plant is unable to obtain the necessary water and nutrients, it declines or dies. However, the evidence of death (needle browning) often occurs at a much later date. An example is Taxus, or yew, planted in a heavy clay sub-soil with no sub-surface drainage. In fall, winter and spring, water accumulates and literally drowns the roots. The tops of the plant may not succumb until the following spring or summer, when hot weather first arrives and stresses the plant. Some evergreens appear to lose vigor and die back after 15 to 20 years. This often is the result of injury to the root system from moisture stresses. Heavy soils may limit development of the root system; root damage easily upsets the top-to-root ratio. Dieback and poor growth are often evident. Changes in sub-soil drainage caused by construction will often cause roots on older plants to die back.

Drought or Dry Soil

The lack of water for long periods may result in symptoms similar to those caused by excess water. Clay soils often pull away from the roots as they dry, drying or breaking the fine roots. Drought stress may be especially noticeable in the summer on evergreens planted on well drained sites (sand or gravel), or where roots are in the top layers of heavy compacted soil. Excessive needle drop and poor vigor are often evident as a result of drought stress.

Reprinted from "Yellowing, Dieback and Death of Narrow-Leafed Evergreens" Factsheet HYG-3034-96, by Stephen Nameth, Nancy Taylor, and Jim Chatfield, the Ohio State University Cooperative Extension.

Landscape - Dieback in Needled Evergreens II

I recently had a question from a landscaper about dieback in evergreens. This year we are again seeing the loss of many evergreens. The following is the second posting on the subject using material from the Ohio State University.

Each year various narrow-leafed evergreens such as pines, Taxus and spruce are affected with needle yellowing and browning, dieback, poor vigor or death. These are problems often associated with one or more environmental stress factors. An explanation of some of these stress factors follows.

Winter Damage

Evergreen plants transpire or lose water from leaves during winter. If the soil moisture is low or roots are unhealthy, moisture in the needles is not replenished and needles are killed. Again, visible symptoms often do not appear until spring or early summer. Damage often appears on one side or on one branch of the plant, usually the side facing prevailing winds. Needles may turn brown one half or one third of the way from the tips. The extent of browning will be similar on all the needles on the branch.

De-icing Salt Damage

Injury from exposure to de-icing salt can occur on plants. Salt sprayed by traffic on wet roads can cause browned foliage, usually on the side nearest the road. Salt solution runoff also can injure plant roots. Entire plants may die. Needle yellowing and browning often begins at the tips and gets progressively worse. Sometimes soil tests conducted in late winter indicate high salts and confirm the diagnosis.

Herbicide Damage

Injury to evergreens by herbicides is difficult to assess. Symptoms are not always pronounced. Needle distortion may be slight, but root damage could be enough to limit water uptake. Tip damage to new growth is a common symptom with some herbicides. Look for needle distortion and twisting, or needle yellowing or browning, depending on the type of herbicide. On spruce, needle purpling and drop is common.

Air Pollution Damage

When atmospheric conditions allow buildup of smog or air pollutants, narrow yellowed bands may develop on the needles of susceptible plants. In other cases, the tips of the needles may turn brown. Ozone injury to white pine will cause a severe reduction in growth. If this continues for years, it is considered chlorotic dwarf disease. Trees under drought stress may be more prone to damage by air pollutants.

Low Light Needle Drop

Most narrow-leafed evergreens need full sunlight. Low light conditions may result in a slow decline of some evergreens such as junipers or arborvitae. An early symptom is foliage drop in the center of the plant. The condition is common on plants existing in overgrown, old landscapes. Sometimes two plants will grow together. Both will begin to decline. In other cases, a deciduous plant nearby may begin casting a shadow on the evergreen plant during the morning or evening hours.

Transplant or Establishment Problems

Improper planting and poor after-transplant care may result in plant decline several years following transplanting. Common problems associated with planting and establishment include: burlap, especially synthetic burlap, left intact around the root ball; strings or wires left around the trunk; planting a containerized plant without disturbing the root mass; inadequate or inappropriate watering following transplanting; support wires left on the tree too long; setting the tree or shrub deeper than originally grown; and settling following transplanting. These problems are difficult to correct after symptoms have become apparent.

Reprinted from "Yellowing, Dieback and Death of Narrow-Leafed Evergreens" Factsheet HYG-3034-96, by Stephen Nameth, Nancy Taylor, and Jim Chatfield, the Ohio State University Cooperative Extension.