Cover cropping basics
Cover crops protect and improve soil between vegetable plantings by fixing nitrogen, adding organic matter, and preventing erosion.
10 min · intermediate
You will learn
- Describe benefits of cover crops for home gardens
- Select cover crops for nitrogen fixation or biomass
- Terminate covers at the right stage before planting
Benefits of cover crops
Cover crops grow during periods when vegetable beds would otherwise sit bare. Their roots hold soil against erosion and create channels for water and air. Leguminous covers fix atmospheric nitrogen in root nodules. Grass and grain covers produce large amounts of biomass that add organic matter when incorporated. Living roots feed soil biology year-round.
Nitrogen-fixing covers
Crimson clover, hairy vetch, field peas, and winter rye mixed with legumes are common choices for home gardens. University of Minnesota Extension cover crop guides help match species to season and following crop. Inoculated seed improves nitrogen fixation in soils without a history of legumes. Allow adequate time after incorporation before planting the next crop so residue breaks down.
Winter-killed and winter-hardy options
Oats and field peas often winter-kill in cold climates, leaving a mulch of dead tops that is easy to plant through in spring. Winter rye survives harsh winters and resumes growth in spring, producing heavy biomass but requiring earlier termination. Buckwheat is a fast summer cover that suppresses weeds and attracts pollinators, ready to incorporate in four to six weeks.
Termination methods
Mow, crimp, or till covers before they set seed and before planting the next crop. Mowing repeated times kills most covers. A roller-crimper lays plants flat as a mulch for reduced-till planting. For small gardens, cutting at soil level and covering with tarp for two weeks is effective. University of Minnesota Extension describes termination timing for vegetable growers.