Monday, March 23, 2009

Greenhouse - Annual Vinca Production

The following is some information on successful annual vinca production in the greenhouse.

Flowering annual vinca is a tough plant that needs a high soil temperature. They grow best at nighttime temperatures between 68 and 72 °F. Keep pH levels between 5.3 and 5.8 for optimum uptake of iron and suppression of Thielaviopsis. Pythium and Botrytis stem cankers are very common on vinca.

Vinca require warm greenhouse conditions to grow well. Heating the greenhouse to 70 degrees F at night is expensive, but if you wish to grow quality vinca, it is necessary. Bottom heat will greatly improve this crop's seedling growth and accelerate transplant flower production. Installation of in-bench soil warming systems will be a wise investment in greenhouses if you grow large amounts for Mother's day. However, a more economic solution is to grow this crop much later in the season. Warmer outdoor temperatures and increased sunlight make production a bit easier. In Delaware, ordering larger plugs of this crop for transplanting into containers in late March through April and growing them out during warmer weather with longer day lengths is a very sound decision.

With vinca, the larger plug sizes have an advantage in that the increased amount of root system greatly improves survival and regrowth after transplant. The development of a strong root system after transplant is essential for success. Most growers purchase 512s or 288s for spring bedding production. However, growing small vinca plugs under cool condition limits how fast a root system will develop. Put a small 512 plug in a 4-inch pot where the soil is likely to stay wet due to the small root system, and you will increase the chances for disease and root damage due to over-watering. Purchasing larger plugs, such as 144s, provides more root development in relation to the pot it is planted in and reduces the time it takes for roots to grow throughout the new media. Larger plug sizes perform better, grow quicker and are essential for early spring crops.

Information from the March 20, 2009 edition of the Greenhouse TPM/IPM Bi-Weekly Report from the University of Maryland Cooperative Extension Central Maryland Research and Education Center and from "A Guide for Commercial Production of Vinca" by Paul Thomas, Jean Woodward, Forrest Stegelin and Bodie Pennisi, The University of Georgia

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