If you’ve been considering sowing a winter cover crop in your vegetable garden, now is the time to do it. In the Piedmont region of North Carolina, there are two types of winter cover crops — winter-kill cover crops and winter hardy cover crops. Choosing one over the other is a matter of patience — as each dictates a timeline for you to get back to planting edibles again.
Winter-kill cover crops are typically planted in late summer, grow throughout fall and will be killed by freezing temperatures in the winter. Come March, if you know you’ll be chomping at the bit to plant early spring vegetables such as snap peas, lettuce and radishes, then a winter-kill cover crop would be ideal.
Winter-kill cover crops include oats and field peas. Oats grow quickly, forming a thick mat, and field peas are a nitrogen fixer. Both help to build up soil biomass, replenish organic material and suppress weeds. When freezing temperatures kill these crops, the dead plant material forms a protective, organic mat on the soil surface, which has a couple benefits of its own.
The dead plant material of winter-kill cover crops can help serve as a weed barrier for early spring edible crops. It also helps protect the soil from erosion and offers a habitat for overwintering insects and pollinators.
The Forsyth Cooperative Extension recommends planting a winter-kill crop by mid-August, to give the seeds sufficient time to germinate and grow to maturity before the first killing frost. However, over the past few years, we’ve experienced prolonged growing seasons, as warmer weather has stuck around a bit longer than normal. If you plant now, you can still see benefits from planting a winter-kill cover crop.