A cover crop is a temporary place holder, as I like to think of it, that is usually grown in the cold season when you're not growing your garden. The cover crop helps prevent soil erosion, improves soil quality and fertility, aids in building soil nutrients and can ward off weeds and pests.
Some common cover crop seeds are crimson clover, field peas, hairy vetch, Austrian winter peas, rye, buckwheat, and alfalfa. You can even plant a combination of these seeds together.
Austrian winter peas.
When you sow these seeds while winterizing your garden they will grow in the early spring and add much-needed nitrogen to your soil. Nitrogen is a beneficial element that is necessary for soil fertility and quality and which is often low in garden soil.
If you want to turn your cover crop into green manure, simply till or turn them over into your soil in the spring before they flower or go to seed. This provides added nutrients and organic material to your soil.
If you’re not planning on tilling or turning your soil, you can pull them out and throw them in the compost pile. Just by growing them you are helping your garden by adding nitrogen to the soil.
Hand-painted sign by Marybeth with Wasatch Community Gardens.
Even if your soil appears to be perfectly healthy, planting a cover crop is good practice in keeping soil fertile, avoiding erosion, maintaining soil nutrient levels, and breaking up hard or compacted soil.
On that note, it’s a good idea to periodically have your soil tested. You can send a soil sample into the Utah State University Analytical Lab (USUAL) and they will send you an analysis of your soil’s pH, salinity, phosphorus, and potassium levels. They offer a number of different tests. If you’re unsure what to test for, you can always call and talk to someone, or find out more information on their webpage.
Many green thumbs assume their soil is perfectly healthy, but the test results can often come as a surprise. For example, if the USUAL analysis shows the soil as having high levels of salinity, the garden experts would recommend avoiding horse manure because it’s often high in salt, and instead use blood meal and cover crops to benefit your soil.