Managing pH is one of the most important aspects of soil fertility and soil health in turf and landscapes. As fall planting season approaches, take measures to assess soil pH and ammend soils as needed.
Late summer/fall planting season for turfgrasses, perennials, and cool season annual beds is coming up. It is important to not to forget pH management as you prepare soils for planting. If you have not done so already, take soil samples from areas to be planted and send to an accredited lab (such as the UD Soil Testing Lab) for pH and mineral nutrient testing. The test results will provide information on lime requirements – both rate and type of lime to use for standard plantings (or soil acidifying requirements for acid loving plants).
Most woody plants can tolerate a wide range of pH’s; however, perennials, annuals, and turfgrasses are more sensitive to pH. For the majority of these plants the ideal pH range is 6.0-6.5. If pH values are below 5.3 root growth will be impacted, toxic levels of Aluminum and Manganese may be present, and you may see deficiencies of Magnesium and Calcium. If an area has been over-limed in the past and the pH is above 6.8 you may see micronutrient deficiencies such as Manganese or Iron (especially in turf). For acid loving plants (blueberries, Azaleas, Rhododendrons) that thrive in pH’s below 5.4, elevated pH can result in poor growth and micronutrient deficiencies.
Gordon Johnson, Extension Agriculture Agent, UD, Kent County.