In your reading about how to vegetable garden, you might come across a thing called “cover crops.” To me, that always sounded like something that a huge commercial farmer would use, not a simple backyard gardener like me. But cover crops are great for gardens of any size and in nearly any climate, because they perform a variety of duties in keeping your garden healthy and thriving. Better yet, it’s as simple as sowing a packet of seeds — if you’ve over-seeded a bare patch of your lawn, you can sow a cover crop.
First things first, though — what exactly is a cover crop? Cover crops are plants that put back into the soil what other plants take out. They are not harvested for food; rather, they are turned back over into the soil at the end of their growing season where nutrients are added to the soil as they decompose. So, cover crops are grown not for your food, but for the soil’s food.
Edible plants like vegetables and herbs use a lot of your soil’s nutrients in order to set fruit or leaves, so it’s our job to add those nutrients back in, and one great way to do that is with cover crops. So, say you’re at the end of your vegetable season, and you want your garden to rest over the winter. Don’t just pull out your summer and fall veggies and call it good, though — bare soil invites erosion, weeds, and loss of precious nutrients, so let’s cover it up. Here’s a list the three main cover crop options — you can order seed online or purchase it at your local feed store or garden center.
Legumes: Legume crop covers include clover (crimson, red, Dutch white, berseem), hairy vetch, fava beans, bell beans and Austrian winter peas.
Grasses: Oats, barley, winter rye, and annual rye grass.
Other Crop Covers: Buckwheat, oilseed radish and mustard.
Find the Ideal Cover Crop for Your Garden
Because not all cover crops provide the same benefits, you’ll want to look for a mix that addresses the issues you’re having or the goals you want to accomplish in your garden. However, it’s a delicate balance — your aim is to choose a mix that contains complementary, rather than competing, cover crops.
Nitrogen uptake + compaction busting: The radish, crimson clover, and triticale combo works well here. While the last two cover crops help to cycle nitrogen (making it available for the next crop), the radish’s taproot busts up soil compaction. Legume cover crops are the masters at adding valuable nitrogen back into the soil.
Weed suppression + nitrogen uptake: Try oats and hairy vetch, a powerful cocktail that not only holds weeds down but allows the next crop you plant to utilize soil nitrogen (nitrogen uptake). A side benefit? The hairy vetch is pretty good at erosion control, too. Grasses are cold, hardy crops that suppress weeds and add tons of organic matter back into the soil. Their root systems are also great at breaking up compacted soil or clay soil, the death knoll for a healthy garden.
Nitrogen fix + organic matter + weed suppression: A pea and oat mixture might work for you. Peas provide a nitrogen “fix” to the soil (and add valuable organic matter) while the oats suppress weeds and act as a “nurse crop” for what you plant next. Nurse crops help aid other crops in getting established, but the oats also provide a kind of living trellis for the pea vines to grow upon.
Nitrogen fix + Pollinator magnet: A mix of clovers can do the trick! Red, ladino, and sweet clover work their magic together by adding valuable nitrogen to the soil while providing valuable food for pollinators like bees.
Can I Create My Own Cover Crop Mix?
While many mixes are readily available and take the guesswork out of successful combos, it is possible to create your own custom mix. Take the following into consideration, and call your county extension office if you need assistance.
- Make a list of the top 2-3 garden/plant/soil issues you’d like to handle with your cover crops
- Research various crops that address your top concerns
- Narrow your cover crop mix down to 2-5 different crops
- Ensure that your cover crop combo is compatible in terms of planting times and complementary growth habits. For example, you want to avoid planting a mix of two cover crops that are both slow to grow, as that can allow weeds to take hold in the meantime. Similarly, a cover crop that puts nitrogen into the soil should not be planted with a cover crop that takes nitrogen up for later use — they will work against each other and you’ll be disappointed with the result.