Which cover crops are still in season?

Concern over availability of common herbicides like glyphosate and glufosinate in 2022 have some farmers thinking about adopting cover crops this fall to suppress weeds in fields intended for soybeans next spring.

Keith Berns, who co-owns Green Cover Seed with his brother, Brian, offers advice for growers thinking about cover crop adoption. The Bladen, Nebraska, soil health advocate says the No. 1 question growers have is: How late is too late to plant cover crops?

"The answer depends on where you are located and what your current and forecasted conditions are," says Berns, whose business is located near Bladen, in south-central Nebraska, where – although the average first frost is October 7, the forecast for that date this year is in the 70s (°F.) and 80s with lows in the 40s and 50s.

"This warmer weather will shift our recommendations to plant later than in a normal year," he says.

What to plant?

Growers have several options heading into late fall.

Winter peas can be planted about the same time as farmers would plant winter wheat. Plant deep to protect the growing point in the winter, Berns says. "Hairy vetch is the most cold-hardy of all of the legumes, and we would plant this at least two weeks past our average first frost date," he adds, with a caveat. "The later it gets planted, the slower it will be taking off in the spring, so be patient."

Several species of cereals will work, Berns says.

Triticale and winter wheat may be planted two to three weeks after the first frost date, and will be fine in the spring, he adds. Cosaque winter black oats and annual rye grass should be planted a few weeks before the first frost, if possible.

Cereal rye is the most flexibile and forgiving cereal crop. "We have had successful plantings through December with cereal rye, so when it is too late for everything else, you can still give [it] a chance," Berns writes in his October 6 newsletter. "It will sprout at 34°F. so will almost always successfully vernalize and be ready to take off and grow fast with the late winter/early spring warmup."

Brassicas, Berns says, are more delicate. Mustards should be planted at least three weeks before the first frost; radishes, one week prior to first frost and turnips up to frost. Collards, rapeseed, and kale can be planted one to two weeks after the first frost.