Cover crops, also known as green manure, help cover and improve soils that aren’t being cultivated for production. Cover Crops also improve tilth. Tilth refers to the structure, or physical suitability for planting. Available at the Snohomish and Monroe Co-Op, explore our selection of cover crops like Field Peas, White Dutch Clover, Crimson Clover, Common Vetch, and a 5-Way Cover Crop.
Grasses like Rye and Buckwheat are easy to germinate, high growing, and will suppress weeds. Clovers and vetch are low growing and provide lots of green manure to return nutrients to the soil. Legumes are nitrogen fixers, but need a little more care when planting. Mixes help utilize the benefits of all varieties of cover crops. Mixes also help us to learn how the different types of cover crop seed perform in our gardens.
The Pacific Northwest gets a lot of rain, which can deplete our soil of nutrients, and causes soil compaction. Planting a cover crop for the winter will replace organic matter. It will protect soil from rain and erosion, and help to break up compacted soil. Cover crops can suppress weeds, reduce runoff and water erosion, and can attract beneficial insects by providing pollen and nectar.
Legumes, like Austrian Winter Peas and Field Peas, have the ability to fix nitrogen from the atmosphere. This is different from other plants, which can only absorb nitrogen available in the soil. Legumes have a symbiotic relationship with a bacteria called Rhizobia. These bacteria form nodules on legume roots, fixing nitrogen. When legumes are tilled under, and allowed to decompose, nitrogen is released into the soil to become available to future plants. Legumes generally need to be established earlier in the year, like mid-September, when temperatures are still warmer. Legumes don’t provide as much erosion control as cool weather grasses. They also don’t do as well in wet soggy soils with a low pH.
Common Vetch generally overwinters well in the Pacific Northwest. It has fewer tendrils than other types of vetch, making it easier to turn under. It is also less likely to become a weed. Common Vetch is a good choice where early spring crops will be planted the following year. However, it’s not as good as grasses at competing with other weeds. Common Vetch grows best when planted in the first half of September.
Crimson Clover is a low-growing cover crop. It is easier to turn under than Vetch, and is less likely to become a weed. It is a good option for areas where early crops will be planted the following year, but it does not compete well with weeds. Crimson Clover grows best when planted in the first half of September.
Dutch White Clover grows as a perennial in the Pacific Northwest and has a fantastic ability to add large amounts of nitrogen. White Dutch Clover also performs well as living cover for permanent pathways and is ideal in orchards and vineyards and as forage for non-ruminants. Dutch White Clover was once the preferred plant for lawns, and will stay small when mowed regularly. Proper management can provide blossoms throughout the season and serve as a pollinator attractant when other beneficial plantings have finished flowering.
Cover Crops planted earlier in the season recover more nutrients, cover the soil more quickly, and produce more organic matter. You can begin planting cover crops as soon as harvest is complete. To prepare your garden for fall cover crop seeding, make sure the soil is moist to allow for germination. Broadcast your seeds at a rate of two pounds per five-hundred square feet. After broadcasting, gently rake seeds into the soil. Cover your seeds with ¼ to ½ inches of soil mixed with an organic compost from G&B Organics, and press down. Seeds need to be in contact with damp soil to germinate. Make sure to plant your cover crop before night temperatures drop below 40 degrees. Because soils are cooler at this time of year, germination can take about two weeks to start.
Available at the Snohomish and Monroe Co-Op, find different cover crops like Dutch White Clover, Crimson Clover, Field Peas, and vetch. Or bring home a bag of our 5-Way Cover Crop mix, which provides a variety of cover crops. The mix includes Cereal Rye, Common Vetch, Buckwheat, Crimson Clover, and Austrian Peas. Austrian Peas, a legume, will add nitrogen to the soil. Grasses like Cereal rye, and Buckwheat will establish quickly to prevent erosion, and suppress weeds. Vetch and Clover will provide lots of green manure to till under in the spring.
Protect your gardens from soil compaction and winter weather erosion. Visit us at the Snohomish and Monroe Co-Op to get your cover crop seed and soil amendments. You’ll love the difference your garden grows in the spring after providing protection and nutrients from a generous planting of cover crops.
We’ll see you at the Co-op!
