Double Duty Cover Crops

Improve your garden's soil by planting and eating these vegetables.

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Turnip in the Garden

Turnip in the Garden

Turnips are cold hardy root vegetables that help improve soil.

Photo by: Debbie Wolfe

Debbie Wolfe

Turnips are cold hardy root vegetables that help improve soil.

Taking Care Of The Soil

Cover cropping is one of the best ways to improve garden soil. In fact, leaving a portion of the garden in a mixed cover crop for a growing season—or better yet a full year—can have an enormous positive impact on fertility. The improvements take the form of increased organic matter in the soil, better water holding capacity, higher nutrient levels and larger populations of active beneficial soil microbes. The difficulty lies in the limited space that most home gardeners are working with. How can you grow a garden and let it rest at the same time? Consider planting “double duty” cover crops.

Multitasking Plants

Home gardeners mostly throw traditional cover cropping out the window. Most of us will not plant wheat, tillage radish or even sweet clover in our veggie patches. We want to eat our harvest! To enjoy the benefits of cover cropping, home gardeners should use those veggies we like to grow for our tables. When plants feature the benefits of cover crops along with edibility, they are considered  “double duty” cover crops.


The cabbage family offers a wide pallet of flavors and colors. They also work wonders for the soil. This group, which includes such varieties as mustard, turnip, radish, kale, broccoli and others, releases biotoxins through their roots which inhibit the growth of many weeds, diseases and insects. The mustards are particularly well adapted for this function. Additionally, brassicas are nutrient scavengers, particularly kale, mustard and turnips. when tilled into the soil at the end of their useful lifespan, they release all of that stored plant food for ensuing crops. Finally, the deeply tap rooted daikon is closely related to the “tillage” radish, and can jackhammer its way through hardened soil layers.

Mississippi Silver Cowpea in Flower

Mississippi Silver Cowpea in Flower

Cowpeas are great soil enhancers and easy to grow.

Photo by: Debbie Wolfe

Debbie Wolfe

Cowpeas are great soil enhancers and easy to grow.


Peas and beans are some of the most popular backyard veggies. They also harvest and store atmospheric nitrogen which becomes plant food for later crops when the spent peas and beans are tilled into the soil. Some of the edible legumes, like pole beans and cowpeas, are also good producers of biomass which adds to the long term organic content of the soil.

Grains Revisited

Those who think that backyard grains are not practical have forgotten that sweet corn is a grain. One of the top three home-grown “veggies” is actually a member of the Poaceae (grass) family. Sweet corn is a heavy biomass producer and a wonderful scavenger of nutrients. Other small grains with similar positive traits, such as wheat and rye, can actually be far more productive in the backyard garden than is commonly known. The grains are easily harvested and may be used either whole or ground into flour. 

Putting it All Together

The challenge to backyard gardeners’ thinking is that cover cropping is not done in neat rows. Instead, it maximizes soil coverage by blending multiple species across the spectrum of plant families in a more natural pattern. Both above and below the soil line, the various plants in the mix take their respective places: some growing straight and tall, others rambling close to the ground, some with broad, shallow root systems, others with narrow deep tap roots. In short, mixed cover cropping seeks to replicate a “wild” or natural plant ecosystem. This system includes nutrient scavengers, nitrogen “producers,” biomass builders, subsoil tillers, natural fumigators and other role players that give your garden a healthy retreat from cultivation. Including double duty cover crops in this system gives the gardener a piece of the action as well.

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