Cover Crops are Bouncing Back after a Tough Winter

Posted: April 14, 2015

Now that the snow is finally gone it is time to evaluate your cover crop stands.

We were not sure what to expect with the record lows we have experienced but are pleased that cover crops that were planted in a timely fashion came through the winter mostly unscathed. A field of hairy vetch and oats in Centre County shows a very nice hairy vetch stand in winter-killed oats.

Hairy Vetch Emerging from Winter Killed Oats
Hairy Vetch emerging from winter-killed oats.

Crimson clover planted after small grain harvest is also growing very nicely as shown on this picture taken today.

Crimson Clover

The tops of red clover frost seeded into wheat last year died off over the winter, leaving a tremendous mat of crop residue.

Red Clover Frost Seeded into Wheat

The new growth, however, is coming through already. The growth of these leguminous cover crops is now very fast and they fix lots of atmospheric nitrogen. By letting them grow for another three or four weeks there will be a significant nitrogen credit for a summer grass like corn, sorghum or sudangrass, while the biomass will provide soil protection, food for soil organisms, and contribute to organic matter maintenance. A cover crop that seems to have suffered most from the winter is annual ryegrass. This grass does not go into dormancy which may be one explanation why its winter survival was less successful. We also hear reports that winterkill was associated with lush fall growth of more than 6”. It is well known that when annual ryegrass goes into the winter when it is this tall it is likely to winterkill. A good practice would have been to mow it to 4” in the fall. Later planted annual ryegrass that was smaller going into the winter may not have suffered from the winter. Finally, snowmold may be another explanation, although the other cover crops would also have suffered from this and do not show any signs of it. The more common cover crops such as rye, wheat and barley seem to have come through the winter without a scratch. If you have observations (preferably with a picture) on cover crops please send them to me at

Contact Information

Sjoerd Willem Duiker
  • Associate Professor of Soil Management and Applied Soil Physics
Phone: 814-863-7637