Cover Crops 101….Keep it Covered!

By Farmer Richard

In our newsletter article two weeks ago entitled “Soil….Our Hope for a Climate Solution,” we briefly discussed the importance of using cover crops as a means of “regenerative farming” to not only build soil, but also as a means of capturing atmospheric carbon through plants and storing it in the soil.  This week we want to share more about what it means to plant cover crops on our farm and why we consider them to be an important part of our production system.  We’ve been using cover crops for over 40 years, mainly as a means of enhancing soil quality.  Only recently have we learned that cover crops are an important tool we can use to help mitigate climate change, both by reducing excessive atmospheric carbon as well as their role in making our soils more resilient to erratic weather conditions.  We know that soils with high organic matter hold water better in drought conditions and are able to drain better in times of excess moisture.  There are many benefits to including cover crops in farming systems and, from a farmer’s perspective, I can’t understand why every farmer wouldn’t want to plant them!

Cover Crop starting to grow just before winter settles in.

Leave no ground exposed for the winter!

Cover crops are crops we plant in our fields before and after our vegetable cash crops.  While we plant vegetable crops with the intention of harvesting them for sale, we seldom ever sell a cover crop.  There are other reasons why we plant cover crops.  Our farming system developed from the work of Rudolf Steiner, JI Rodale, and William Albrecht, early advocates of using cover crops in organic systems as a means of keeping the ground covered at all times. In theory, this is a basic principle of nature that allows us to use plants to capture solar energy from the sun to enrich the soil and prevent erosion.  We don’t like to have bare ground over the winter as it is very vulnerable to winter winds, etc and we don’t want to lose our precious topsoil!  Cover crops, in certain locations, also help to filter and purify water to keep our waterways clean, and enhance and encourage biodiversity of soil microorganisms that help us increase the organic matter in our soil as well as hold nutrients in place so they are available for the next vegetable crop that will go in that field.  While this all makes sense in theory, in practice it all comes down to management! 

Many of our long term crew members understand our goals with regards to planting cover crops, but in the heat of the busy late summer and fall harvest season when we need all available hands on deck to harvest, it’s easy to put planting cover crops on the back-burner

to plant another day when harvest is done.  However, our crew members understand planting cover crops is a priority and work diligently to make sure they get planted as soon as possible.  As soon as we finish harvesting a crop and are done with it for the season, we prepare the ground and plant the cover crop even if it’s just two beds out of the entire field!  Time is of the essence in the fall and our goal is to give the cover crop as many growing days as possible to get established before the temperatures drop and winter sets in.  Cover crops may also be planted into a standing vegetable crop at the time of last cultivation.  This allows us to have a soil-improving cover crop already growing in the shade of a cash crop, ready to take over as soon as the cash crop is done and any remaining portion of the plants are chopped!  We use this method in crops such as asparagus, strawberries and rhubarb.  In these scenarios, the cover crop not only enhances the soil by increasing organic matter, but the cover crop also helps to compete with weeds and forms a mulch of sorts when the cover crop plant “winter kills.” 

Japanese millet planted in between rows of strawberries.

We have two main cover crop mixes we plant.  One mix includes plants that will “winter kill.”  Even though we may get some frosty nights and cold temperatures late in the fall, the plants in this mix continue to grow, albeit slowly.  Once the ground freezes solid their growth stops.  This mix includes Japanese millet, oats, field peas, crimson clover and a few other clover varieties. The benefit to planting a cover crop that winter kills is that the plants will not grow again in the spring and we can prepare that ground early in the spring to plant vegetable crops since the cover crop residue will work into the soil very easy without a lot of green crop plant matter to get in the way. 

An Austrian Winter Peas cover crop, notice the
the white nitrogen nodules already forming on the roots this fall.

Our second mix consists of plants that can go dormant during the winter, and then resume growing again in the spring.  We plant this mix in fields that we won’t need to plant very early in the spring.  This allows us to leave the cover crop in the spring so it can grow and we can maximize its benefits.  We usually cut or chop the cover crop just before it goes to seed.  This mix consists of cereal rye, rye grass, mammoth red clover and hairy vetch.  In addition to serving as a sponge to take up available nutrients and hold them in place for next year’s crop, the rye also makes a good mulch that we cut and bale.  We take the bales off of one field and put them on another field to mulch in between beds of vegetable crops such as strawberries, tomatoes and garlic.  The clovers and vetch are able to take nitrogen from the air and fix it in the soil, which means we don’t have to apply fertilizer!  If we have excess rye grass beyond our needs for mulch, we may choose to bale some to use as feed for our cattle and goats through the winter or sometimes we just chop the crop back onto the field and work it into the soil.  This is referred to as a “green manure” crop.

Even our cold frame greenhouse gets a cover crop!

We have embraced this practice and are always looking for ways to improve the system.  Over the past few years we’ve increased the diversity of plants in our cover crop mixes.  While it is more complicated to make these mixes, we appreciate the plant diversity and the different beneficial attributes each plant brings to the mix.  We will continue to invest both time and resources into planting cover crops as the benefits of doing so far outweigh any management challenges we may juggle.  Maintaining and improving the health and resilience of our soils is crucial to our ability to continue to produce vegetables with maximum nutrient quality.  We also want to do our part to maintain clean waterways, prevent soil erosion and maximize CO₂ capture through our practices to do our part to mitigate climate change. 

As we continue our conversation about the future of our food system and what we want it to be, we feel it is important for you, the eater, to understand the growing system and practices we employ.  Not all food is created equal and it’s up to you to make an informed decision as to what type of farming practices you want your food purchases to support.  There are some conventional, chemical farmers who are trying to improve their soil quality with cover crops and are taking advantage of the assistance and incentives offered by the NRCS (Natural Resources and Conservation Services).  While this is good, it’s hard to make much positive headway when the cash crops being planted require chemical inputs that damage and degrade soil as well as cause other problems to the ecosystem and environment around them. 

We hope you too can appreciate the benefits of cover crops in an organic farming system and will choose to support local producers who prioritize integrating cover crops into their agricultural systems.  We’ll do our part, but we need the support of consumers to turn the tide and shape our food system into the future.