Our top crops in terms of revenue are tomatoes, melons, and flowers. This isn’t a ranked list, the exact ranking changes between years and is a contentious and competitive topic among the folks in charge of those respective crops. As all three start to wind down, it’s a fitting time to talk about another very, very important crop and the one that takes up the most area at the farm: cover crops!

A cover crop is something grown primarily to benefit the soil, not a cash crop to be harvested and removed from the land. When we grow a cover crop, we’re growing food for soil microorganisms (bacteria, fungi, protozoa, nematodes, earthworms, and arthropods, etc.) which will eventually feed subsequent crops grown in that field. While the cover crop grows, those plants absorb carbon from the atmosphere and release sugars and other nutrients into the soil, feeding the below-ground ecosystem. When the crop is terminated (mowed with a tractor or grazed) and added to the soil, it further feeds the soil microbes. Like humans, soil microorganisms benefit from a diverse diet, so we grow a mix of species in our cover crops. The more diverse the system above ground, the more diverse the system below. A diverse and healthy soil ecosystem creates healthy, robust soil that fosters healthy, resilient plants and leads to more flavorful and nutritious produce. In addition, by covering the soil, these plants are helping it stay in place, avoiding erosion from rain and wind. Growing a cover crop has also been shown to increase rainwater retention and there’s ongoing research about cover crops’ role in sequestering carbon and impacting global warming.

The mix of species in our cover crop depends on the season. In summer, we plant a blend of black-eyed peas, buckwheat, cowpeas, sorghum, sudan grass, sunflowers, and sunn hemp, all of which do well in our summer heat. The winter mix includes clover, fava beans, mustards, peas, oats, tillage radish, and wheat. We’ve recently started saving our own winter cover crop seed!

Each plant is chosen for a specific quality and role. Legumes will fix nitrogen (fixation converts nitrogen in the atmosphere into a form that plants can absorb through their roots); large rooted plants will break up the soil (radishes), flowering plants(sunflowers, buckwheat, peas) provide food for pollinators, some will act as a biofumigant (mustards), and all will provide habitat for pollinators and will add biomass to the soil (grasses and grains especially).

Any time you come to the farm, you’re likely to see a cover crop in some stage of its life. Currently we have fields that have just germinated (photo immediately above), getting tall (photo on the top), and being grazed down by the sheep and cows (photos below showing during and after grazing). We like to incorporate the animals into cover crop fields before mowing the grazed field with a tractor and preparing the field for its next planting. By digesting the plant material, they’re adding an additional level of biology to the soil ecosystem and increasing soil nutrient availability.

Cover crops are a long-term investment in soil health. Nutrients aren’t immediately available to the next crop; it may take years! Similarly, improvements in soil texture and water retention take time to materialize. There are immediate costs to growing them too: seed, fuel to power the tractors that will plant and eventually mow, water, and occupying field space that could be used for a cash crop. During low water years, we need to cut back on cover crops and save water for things that generate income. Even considering all those tradeoffs, we think cover crops are worth it and are a key part of how this farm works. Scientific research is still looking into cover crops and their role in soil health and climate change mitigation and adaptation. We hope that more research, plus continued government funding to support cover crop planting will encourage more farmers to grow them too.

Elaine Swiedler, CSA Manager