Many common cover crops, such as oats and oilseed radishes, die over the winter. Others, such as annual ryegrass and cereal rye, usually survive the winter and are killed in early spring with glyphosate or other herbicides.

But managing the spring burndown can be difficult, especially for beginners, warns cover-crop agronomist Hans Kok, coordinator of the Conservation Cropping Systems Initiative in Indianapolis, Ind. In a wet spring, for example, cereal rye can grow very fast and produce heavy residue, which may interfere with planting and tie up. Annual ryegrass can be hard to kill with glyphosate when it’s cool, because the herbicide doesn’t translocate well, Kok says.

Wait to spray until the cover crop greens up and is actively growing, Bowers says. Spray full rates of glyphosate on a sunny day when the temperature is high enough for good activity, Kok adds. And pay careful attention to spray water quality, pH, hardness and spray coverage. Stop spraying by mid-afternoon, Robinson advises.