Maybe after you finish your vegetable harvest, you mentally say, “I’m done this year,” and wait to start again next year. But a cover crop could benefit you in several ways. By researching now, you can be prepared to install cover crops this year.
Like many farmers, home gardeners have been exploring and using cover crops in their vegetable gardens. If you’ve never considered cover crops, let’s examine their benefits and some plant species you could use.
Today, I’ll glean a few insights from the Purdue Extension publication, “Cover Crops in the Home Garden.”
First of all, what is a cover crop? Cover crops are plants grown to improve soil quality or to provide a benefit to the ecosystem. They are generally not harvested, and they are generally sown in late summer or early fall, left through the winter, and terminated or tilled under in the spring. We used to call these crops “green manures,” but I always thought that was a somewhat confusing term.
Some cover crop benefits include reducing erosion, improving soil structure, reducing weeds, recycling nutrients, improving soil fertility, and providing forage and habitat.
Erosion may be less of a concern with a garden on level soil, but it’s a big concern for farmers. Cover crops slow runoff and allow more water infiltration. Besides water erosion, we can also have wind erosion. So, if your garden is in a windy area, you could benefit from a cover crop.
Soil structure has an impact on soil tilth, a term sometimes used synonymously with soil structure. Soil structure is how the soil is held together. Tilth refers to the physical condition of soil as related to its ease of tillage, fitness as a seedbed, and its relative impedance to seedling emergence and root penetration. Cover crops will help you by adding biomass below the soil surface, which in turn enhances soil pore spaces and promotes better water infiltration, drainage, and aeration.
Weeds are the bane of many gardeners. Cover crops compete with weeds for light, water, and nutrients. Some cover crops can also decrease weed growth by secreting allelochemicals from their roots that inhibit the growth of weeds.
Cover crops help recycle nutrients by scavenging for nutrients in the soil that might otherwise be leached out or lost with surface runoff. The cover crop takes up the nutrients, uses them, and then returns them to the soil when terminated or tilled under. New garden crops can use them.
In addition to scavenging for nutrients, some cover crop species (legumes) can be used to increase soil nitrogen content. Legumes are plants that “fix” their nitrogen from the air by means of soil-borne bacteria and nodules on the roots. Thus, some nitrogen is returned to the soil upon termination of the legume.
Finally, aboveground cover crop vegetation can provide food and shelter for numerous animals, including insects, mammals, and birds. Cover crops allowed to flower can provide pollen and nectar to pollinators. Belowground, earthworms benefit from the habitat provided by cover crop roots.
Cover crops come in many types, including grasses, legumes, non-legume broadleaves, and mixtures.
Grasses can include cereal rye, oats, wheat, and pearl millet. Annual ryegrass is used in agriculture, but can be difficult to terminate. When used in the home garden, it can sometimes become a weed.
Cover crop legumes can be white clover, crimson clover, Austrian winter (field) pea, hairy vetch, or sunnhemp.
Non-legume broadleaves include oilseed radish, field turnip, mustard, canola, and buckwheat.
For additional details, including planting dates, seeding rates, and termination methods, search for publication HO-324-W, Using Cover Crops in the Home Garden, at Purdue Extension’s Education Store: https://edustore.purdue.edu/.