If you’re seeding oats and expecting winter temperatures to terminate this cover crop before spring planting rolls around, you may want to rethink that decision.

A number of Pennsylvania growers last winter found temperatures weren’t cold enough to kill their oats as a low-cost way of terminating cover crops. Other growers found the same was true with volunteer oat plants that showed up in the spring with fall-seeded wheat.

In a Lancaster Farming article, Dave Lefever wrote that growers ruled out the likelihood that a lack of winter termination came from contaminated seed, since these farmers sourced seed from different outlets.

Oats Didn’t Die

Todd Irvin, a no-tiller in the State College area, grows 135 acres of wheat and 150 acres of oats on the family’s 1,100-acre operation. He also seeds oats as a cover crop.

He found volunteer oats survived the winter after wheat had been planted into the stubble of the previous year’s oats crop that was harvested for grain and straw in July. With the summer of 2023 having ample rain, vigorous regrowth of the volunteer oats after harvest helped the oats reemerge with the wheat last spring.

Irvin also seeded oats as a cover crop in August after harvesting 75 acres of green beans. While the oats turned brown and appeared to die by February. the cover crop didn’t stay that way.

“It grew back and was as green as could be in May,” he says. “Roundup didn’t kill the oats cover crop on the first pass, requiring a second application.”

Jeff Graybill, a Penn State Extension agronomist in Lancaster County, says seeing oats survive the winter in Pennsylvania was a common occurrence this past spring.

Low-Cost Cover Crop

Sjoerd Duiker, a Penn State soil management expert, promotes oats as a cover crop and forage. “It’s a low-cost cover crop with a lot of benefits,” he says. “As a cover crop planted in September, it emerges quickly to help protect the soil surface, requires relatively little herbicide and provides good quality forage with high sugar content.”

Duiker says it’s rare for an oats cover crop not to die in the winter in Pennsylvania. He believes the trend toward oats surviving the winter is a sign of a changing environment. “I think we’re getting more and more of a reality check that this global warming is happening,” he adds.

In conclusion, while maybe it’s just a fluke with Pennsylvania’s 2023-2024 growing conditions. I think it’s a weather-related situation you may want to consider if you’re counting on winter termination of oats as a low-cost cover crop — whether seeded alone or in a multi-mixture.