While clearing out your garden this fall, there’s no need for it to remain a blank, empty space until spring. If you have a year-round growing season, you can grow winter veggies and flowers, of course. But you can also add cover crops to your garden that improve the soil while you basically sit back and “watch the grass grow” –or the peas, clover and barley.
Cover crops are basically crops grown in the winter months specifically to “fix” nutrients in the soil and improve overall soil health. These plants are usually a combination of grasses, legumes and grains.
If you think cover crops are just for farmers, think again. You don’t need acres of soybeans, almond trees, or lettuce to get in on this climate action.
As a Ph.D. candidate at UC Davis studying agricultural water management, I’ve seen the benefits of cover crops and the role they could play in preparing for the climate challenges ahead. Cover crops help improve the soil, reduce erosion, and decrease the need for fertilizer, which contributes to greenhouse gas emissions.
Not just for farmers
While there has been a resurgence of interest in soil health—including my own dissertation topic—researchers have been studying the benefits of cover crops for more than a hundred years. Farmers have known these benefits for thousands of years before that. Roman farmers were advised to plant their grain where beans were harvested because legumes can increase nitrogen availability, and there are many more combinations of cover crop species and benefits.
UC Davis Ph.D. student Alyssa DeVincentis stands in a field of cover crops–vetch, bell beans and Austrian peas. (Courtesy Alyssa DeVincentis/UC Davis)
But if you think cover cropping is just for farmers, think again. You don’t need acres of soybeans, almond trees, or lettuce to get in on this climate action. Anyone with a backyard garden, community garden plot, or windowsill planter box can grow cover crops.
What should I plant?
Choosing which cover crop to plant depends on the kind of help your garden needs. For instance, cereal rye or annual ryegrass grows fast, strong, and deep to prevent soil erosion. Radishes and sunflowers have tap roots that reduce compaction. Buckwheat and clover can attract pollinators.
Annual plants are a good choice if you’re looking for maximum plant material and are willing to replant every year. Perennials will build a strong root system and reestablish themselves for multiple years.
The USDA’s Plant Hardiness Zone Map can help you make sure the crop you choose will actually grow in your area at the time you’re ready to plant.
As they grow, cover crops take advantage of the sun’s free energy to transform CO2 into plant material. Then once spring arrives—and before they set seed—mow or cut down your cover crops and turn them into the soil. This helps store carbon and nourish the soil for when, after a few weeks of decomposition, you plant new crops of flowers or food.
Alyssa DeVincentis is a Ph.D. candidate at UC Davis studying hydrology in Samuel Sandoval-Solis’ lab in the Department of Land, Air and Water Resources.