Cover crops are gaining ground with home gardeners recently. In the most basic terms, cover crops are any plants that are grown to protect or improve the soil rather than for harvest. This ancient technique is widely used among organic and sustainable farmers, and home vegetable gardeners are discovering its benefits as well.
Sowing a winter cover crop can beautify your winter garden, greatly improve your soil, attract beneficial insects, and lead to an overall healthier, more bountiful garden. Although it can seem complicated at first, the basics of cover cropping are actually quite simple. And since winter cover crops are typically sown between late August and early October in the Pacific Northwest, now is a great time to get started!
Why plant winter cover crops?
The great thing about biological gardening techniques is that they tend to provide multiple benefits at once. Depending on which crops you choose and how you manage them, winter cover crops can do a lot for your garden, all with very little effort from you.
Bare soil can become compacted during heavy winter rains. Compacted soils lead to a whole lot of gardening headaches later. A layer of straw, leaves, or other mulch material can help, but a “living mulch” of winter cover crops is even more effective. The leaves act as a cushion for falling rain, while the roots hold spaces open in the soil.
Cover crops won’t stop weeds entirely, but they’ll at least compete with them. The advantage of cover crops over weeds for winter soil cover is that your cover crops will be much easier to remove when the time comes to replant.
Healthy soil life
Soil is alive with all sorts of microbes, insects, and fungi. All of these organisms are adapted to living in and among plant roots. Think about it: how often do you see soil stay bare for long periods of time in nature? Keeping plant life thriving in your garden all year will protect and nurture your soil ecosystem. You’ll have lush greens instead of barren mud to look at all winter, followed by a blooming mini-meadow in the early spring. Many cover crops even attract beneficial insects.
Restored organic matter
Once spring arrives, you’ll cut down your cover crop, dig it under, and allow it to compost in place. This restores depleted organic matter just like adding a bag of compost, but you’ll have the satisfaction of knowing you grew the organic matter yourself.
Some (not all) cover crops work with associated soil bacteria to pull nitrogen out of the air and “fix” it into a form plants can use. Once the cover crops are tilled into the soil, this additional nitrogen becomes available to whatever crops you plant next. This nitrogen-enhancing power is why legume (nitrogen-fixing) cover-crops are sometimes called “green manures.”
Get started with winter cover crops
Do you have some garden space opening up, maybe as you harvest your spring and summer crops? All you need to give winter cover crops a try is a bag of seed, a rake, some bare soil, and a little basic know-how.
Step 1: Choose your seed
For most home gardeners, the best winter cover crop option is a blend of grains and legumes. Sky sells a pre-made blend called Garden Way that contains both. The grains — triticale (a cross between wheat and rye), walken oats, and annual cereal rye — will grow quickly, providing a thick weed-smothering cover as well as plenty of organic matter to dig in next spring. Meanwhile, the roots of the legumes — Austrian winter peas, common vetch, and crimson clover — will be working with bacteria in the soil to pull nitrogen out of the air and produce natural fertilizer.
Step 2: Prepare the soil
If you’ve been growing food crops in your soil all summer, it’s probably pretty well depleted by now. To make sure that your cover crops can work as hard for you as possible, it helps to add about half an inch of compost to your beds and work it into the top few inches of soil before you sow your cover crop. If your soil is on the acidic side, you might add some dolomite lime as well.
Step 3: Sow, rake, and water
Sowing winter cover crop seeds is easy. The bag will have a rate of application written on it, so just follow those instructions. You can use a seed spreader if you have a large area to cover, or just broadcast the seeds on top of the soil by hand. To make sure your coverage is as even as possible, make two passes at right angles to each other. Once you’ve broadcast the seed, lightly rake it into the top inch or so of soil, and then water.
Step 4: Wait
Now for the even easier part! Just let your winter cover crops grow. If you sow them early in the fall, they may need a little water to get them through any dry spells. But once the fall rains set it, they should be self-sufficient. They will grow throughout the fall, hold steady over the winter, and then prepare to set seed in the spring.
Step 5: Cut down and dig in
Just as the legumes are flowering and the grains are beginning to produce seed heads – but before any of the cover crops set seeds – is the perfect time to cash in your cover crop. Start by cutting or mowing it down, then use a shovel or garden fork to turn the top layer of soil over and expose the roots. Let them decompose for a couple of weeks. This step is especially important if you’ve used a blend containing rye, because fresh rye can actually stop other seeds from germinating. Then gently dig the cover crop residue into the soil. Now you’re ready to plant your spring crops!
We’re here to help
Whether you’re planning to plant cover crops for the first time this year, have questions about your past adventures with cover cropping, or want to try a new method this year, we’re happy to help. Come in to Sky Nursery to see our selection of cover crop seeds and soil amendments, along with samples of cover crops that are already growing. And for more information on year-round vegetable gardening, don’t miss Emily Apple’s seminar on extending the harvest, coming up Oct. 8th.