Gordon Johnson, Extension Vegetable & Fruit Specialist; email@example.com
Small grain windbreaks are a useful tool when planting early warm season vegetables such as watermelons or tomatoes the following spring. Small grain crops planted in early fall will overwinter and then elongate and head in the spring. Depending on the crop used and when they were planted in the fall, they can reach 3-5 feet in height by the end of April. Small grain windbreaks serve two main functions: 1) they provide protection against wind that can desiccate or physically injure transplants and young plants and reduce sandblasting in sandy soils and 2) they help retain heat by reducing convective heat losses of wind passing over plant beds. Small grain windbreaks are particularly useful where vegetables are grown on plastic mulch. They also can serve as a winter cover crop.
Rye has been the preferred windbreak because tall types are still available and it elongates early in the spring. While barley is also early, tall varieties are not generally available. Wheat and triticale are intermediate and later.
Windbreaks are planted in every drive row, between every 2-3 beds or between every bed. Maximum protection and earliness are achieved when windbreaks are used between each bed and black plastic mulch is used for beds. Orientation of windbreaks so they are planted East-West is preferred to reduce shading.
Setting up windbreaks can be done in several ways. A simple method is to plant the field solid with the small grain and then till planting strips using a narrow tillage device (tractor mounted rototiller or multiple passes with a narrow field cultivator) in the spring before it puts on much growth. Tilling bed strips is best done in March. Alternatively, a non-selective herbicide can be used to kill strips in the late winter or early spring and then tilled later. Another method is to set up grain drills to plant 2 or 3 rows of small grain and then block the seed meters to skip the area where the beds will be in the spring. This allows more flexibility in the spring for tilling beds because there is less vegetation to manage. A third method we have tried in demonstrations at our UD Georgetown research station is to plant bed areas with a winter killed cover crop and then rye in the windbreak areas. This is done by dividing up and blocking certain seed meters on the drill. We use a drill with both small grain seed box and a small seed box. We plant forage radish with the small seed box in the area we want to have the bed and block of the other seed meters and do the opposite for the rye in the larger seed box.
It is best to plant windbreaks earlier in the fall to get good fall tillering. The last week in September or first week in October is ideal for most of Delaware and mid to upper Delmarva. Rye can be planted later but will then be delayed in the spring by several days and tillering may be reduced. You should plant at standard rates or higher (120 lbs/acre equivalent or more) for the most effective windbreaks. Higher seeding rates should be considered when planting late.