Is Organic Food Healthier than Conventional Food? Some thoughts on Cover Crops and Health

By Richard de Wilde and Andrea Yoder

Rainbow over one of our lovely fields!

“Is organic food healthier than conventional food?”  This is the question Anneliese Abbott posed in her recent article posted at EcoFarmingDaily.com, and a question many have been debating for years.  In her article, Abbott takes a step back and approaches this question from a broader, more historical perspective.  She brings attention to the fact that we can look at this question with a very narrow, limited focus, or from a more holistic approach.  You see, it’s not just the nutrients in the food that we need to be concerned about.  It’s also the things that are not in the food that affect health, such as pesticides that are detrimental to not only human health, but also the health of our ecosystem.  Which leads us to consider the question, “What is health?”  Is it just our individual physical state?  The absence of disease and the presence of vitality in our bodies?  What if we widened the lens to expand our view of health to not only our individual bodies, but also our communities, environment, and the world as a whole?    We are all interconnected and the health of our community and the environment around us impacts our own personal health both directly and indirectly.  So when presented with the choice of choosing organic food or conventional food, we’re really in a position where we are choosing what kind of a farming system we want to support.

Onion crop with clover cover crop in the wheel tracks.

If you’re reading this article, you are likely a CSA member or a consumer who eats vegetables from our farm and you have made the conscious choice to eat organic food.  We value informed consumers and feel it is important to facilitate the connection between eaters and where their food comes from.  So this week we want to draw your attention to one part of our organic farming system that is very important to maintaining the health of our land, supporting the health of our vegetable crops, and in turn supporting your health!  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, we can’t understand why every farmer wouldn’t want to plant them!

Close up of Mammoth Clover, Rye Grass, and Vetch.

While many of the vegetable crops we grow have shorter days to maturity ranging from 60-90 days, we also plant crops that need more days to reach maturity.  Lets consider a crop that requires 120 days to reach maturity.  So the crop is in the field 120 days.  Given our climate, we can also assume there are about 90 days during the winter when it’s too cold and the weather conditions are such that we cannot grow a crop.  But there are 365 days in a year, so what about the remaining 155 days?  What happens over that period of time in between vegetable crops and the changing of the seasons?  If we work with the laws of nature, we know that Mother Nature does not like to be naked and there is great value in having plants on the land.   This is where cover crops play an important role on our farm.  Once we take a vegetable crop off a field, we turn around and plant a cover crop.  The cover crop will then help hold the soil in place and prevent erosion from winter winds as well as early spring and late fall rains.  Cover crops also help us build soil fertility, maintain and build communities of soil microbes, build organic matter in the soil and replace the nutrients we take off the land every time we harvest a vegetable crop.

The difference one week makes!  Cover crop on the left
was planted one week before the cover crop on the right.

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.  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.

Farmer Richard standing in a cover crop of rye grass.

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, hairy vetch as well as Alice clover and red clover.  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.

Australian Peas holding nitrogen in the soil.

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.  Each variety also supports its own unique microbes that interact with the plant at the root level.  We are also learning that there is also a synergy between organisms that multiplies the benefits exponentially.  Little is know about this interaction, but it is believed that the microbes communicate and function as a larger, very complex organism that can move water and nutrients across the field to plants in need.  Plants and microbes also work together to trade nutrients each may need, but may not be able to produce on their own.  Plants exude simple sugars and carbohydrates on their roots.  These carbohydrates are available for microbes to utilize and in exchange the microbes help make nutrients in the soil more bioavailable for the plant.  This is a very simplified explanation of what is happening at that microscopic level and we are continuing to learn more about this complex and beautiful symbiotic relationship.  What we do know though is that our crops are healthier and produce better and taste better when we have lots of microbial activity in the soil.  So for us, it’s worth the investment in time and money to diversify our cover crop plantings to reap these benefits.

Nicely established September cover crop.

We plant the majority of our cover crops in the month of September, but we’ll continue to plant them in fields as we finish harvesting crops.  Our goal is to maximize their growth potential in the fall, but after October 15 we realize the time on the growth clock is pretty limited.  At that point in the season will start planting only perennial rye seed and we’ll do so at 2-3 times the normal rate in hopes that if we can at least have a short stature, but thick, stand of plants that will be able to hold the soil in place.  Even if we don’t have much height above the surface, the root system and below ground biomass will be established.

Even though we plant cover crops every year, we continue to be amazed at the difference they make in our farming system.  We’ve spent over $6,000 on cover crop seeds that we’ll plant this fall.   We’ll also be investing in a lot of compost as well as minerals that will be applied to fields before winter.  The dollars add up and sometimes we ask ourselves “Is this really worth it?”  The answer is always “Yes” and we consider the investment to be one of those non-negotiables.  At the end of the day, you can be the judge as to whether or not it was worth the investment.  What do you think?  Is organic food healthier than conventional food?