Nourish Your Soil with Cover Crops
As the seasons change and the time comes to put your annual plants to bed for the winter, what happens to the bare soil? Though it’s not always the most glamorous part of gardening, soil is at the heart of everything you grow. Exposed soil can quickly erode and lose nutrients when it rains, while the empty spaces invite fast-growing weeds. Planting temporary ‘cover crops’ in the fall is a great way to ensure your garden beds are in top shape for spring planting. Adding these crops to your garden rotation can help control erosion, hold onto vital nutrients, and feed the soil with organic matter. Cover crops nourish your garden by naturally building quality soil.
Benefits of Cover Crops
Cover crops provide a range of benefits during a time of year when garden spaces would typically go unused.
- Retain Minerals
Cover crops uptake minerals through their roots and into their cells, preventing critical nutrients from leaching off during the rainy season to be available to future plants. Some cover crops, like legumes, even add nitrogen to the soil.
- Add Organic Matter
Plants decompose into rich organic matter that aids soil structure, holds onto moisture, and provides a food source for beneficial microorganisms.
- Suppress Weeds
Intentionally planting cover crops leaves very little space for eager weeds to colonize bare patches of soil. A densely planted cover crop prevents germination and growth of weeds.
- Control Soil Erosion & Compaction
Roots control erosion by physically holding the soil in place against rain and wind. At the same time, roots reach down to aerate the soil and prevent compacted soil beneath the surface. Cereal grains like buckwheat, oats, and rye have especially robust root systems to help break up hardened clumps, allowing future crops to grow without that barrier.
Feeding the Soil
One of the most important nutrients for plant growth is nitrogen, the most abundant element in our atmosphere. The problem is that most plants can’t directly use the nitrogen in the air all around us.
Certain plants like legumes (including common cover crops like red clover, peas, and fava beans) have evolved symbiotic relationships with soil microbes that transform nitrogen into a form that plants can use. Other cover crops like oats and rye grab onto what nitrogen is already available so that it can be recycled back into the soil when their organic matter decomposes. Buckwheat helps draw phosphorus, another important element for plant growth. These are the same components you add to your garden with fertilizers, so introducing cover crops to your rotation can allow you to naturally increase these nutrients in your soil.
Varieties of Cover Crops
| Crimson clover - 1.2 - 2.5 lbs per 1000 sq. ft. | Peas - 4 lbs per 1000 sq. ft. |
| Buckwheat - 3 lbs per 1000 sq. ft. | Oats - 4 lbs per 1000 sq. ft. |
| Fava Bean - 3 lbs per 1000 sq. ft. | Rye - 2 - 4 lbs per 1000 sq. ft. |
Steps for Planting Cover Crops
Cover crops are typically sown in autumn or spring. Sow seeds densely (see recommendations for different crops) into bare, moist soil.
The most important step is terminating your cover crop — once they’ve grown tender vegetation but before the crop goes to seed, cut or mow down the plants and fold the fresh growth into the earth. Within a few weeks, the cover crop will begin to break down into rich organic matter. Depending on what you choose to plant, cover crops like red clover may be “winter-killed” to begin decomposing on their own if the temperatures drop low enough. Other cover crops like fava beans will grow through the cold season, so cut them before they go to seed and allow several weeks to begin decomposing into the soil before you begin your regular planting in the spring.
Prep Your Garden for Success
Cover crops can be a great addition to your fall gardening routine, offering a low-maintenance way to improve your soil over the winter. Keeping roots in the ground all year round helps maintain a healthy soil biome and enrich your soil for future planting. Try growing a cover crop this fall and, if you run into any questions, our experienced gardeners at Cornell Farm are here to help.
