Growing strawberry plants under canopy-like structures called low tunnels in the mid-Atlantic region of the U.S. could extend the growing season of strawberries, according to scientists from the Agricultural Research Service (ARS).
At the Genetic Improvement of Fruits and Vegetables Laboratory in Beltsville, Md., geneticist Kim Lewers is testing strawberry varieties with this new system designed to extend the growing season in the northern and eastern parts of the U.S. Lewers is working with horticulturist John Enns and his assistant, George Meyers.
Low tunnels are canopies made of long sheets of plastic laid over support hoops that hold the cover about 30 inches above the strawberry bed. The structure protects the plants against rain and harmful infrared and ultraviolet rays, and can capture heat during the spring and autumn, when temperatures are lower.
Since plants are protected against rain, the tunnels minimize the chance for the appearance of two strawberry diseases known as Botrytis and anthracnose. Botrytis tends to occur in cold and humid conditions, but anthracnose happens in hot and humid weather.
According to Lewers, strawberry growers also use high tunnels, but these can be problematic because humidity condenses more in them, which can increase the chances for Botrytis and powdery mildew. In lower tunnels, humidity remains the same as that of ambient conditions.
The peak strawberry season in Maryland usually takes place from mid-May to mid-June, but with the system used by Lewers, production starts earlier in the spring and continues until the autumn. During several months, the performance under these tunnels can be the same as that of crops in California.
There are no patents on the plants used by Lewers. They are available freely without the need for any special license.