Cover Up with Cover Crops

etc.usf.edu

    “Don’t leave garden soil naked,” recommends the Union of Concerned Scientists, in their second tip to help create a climate friendly garden, http://www.climatefriendlygarden.org. They suggest that you, “Stabilize, build, and add nutrients to garden soil that would otherwise remain bare by planting winter cover crops such as grasses, cereal grains, or legumes.” This practice also keeps carbon from being released into the atmosphere. 

     Last fall I spent a morning in my sister’s kindergarten classroom sharing the value of cover cropping with a group of extremely enthusiastic gardeners.  We acted out: an oat growing—struggling to push the soil apart; dying—laying down its grasses; and then a tomato plant easily growing in its place.  The young gardeners demonstrated the science behind cover cropping by drawing the step by step process of an oat plant growing long roots into the soil; dying--covering the ground with biomass; and then its decaying roots opened spaces to allow the tomato plant’s roots to grow easily.  At five and six, they already understood the benefits cover crops offer their school courtyard garden.

Oat cover crop capped with icy snow.

     In my home vegetable garden, I've used oats as a cover crop for the past few years.  I cut the oat grasses back to approximately a foot high when they look close to "going to" seed, to keep the seeds from becoming future “weeds” among the vegetables.  This annual (a plant that needs to be replanted each year) requires no rototilling--turning over of the soil--in spring. I simply move the dead grasses aside, and plant the seedlings in the soil, allowing the new roots to tunnel through the oat roots’ open pathways, while the die-back left from the grasses protects the soil like mulch. 

     There are a number of other cover crops available (peas, beans, clovers, and other legumes) that will “suppress weeds, prevent erosion, improve soil fertility, store carbon, and supply all of the nitrogen needed for the next season’s plants to thrive.”
    It may be a while before I can plant my seedlings among my garden’s oat debris this year, since there is currently a foot of icy snow covering my cover crop.

Barbara Pleasant offers information on specific cover crop plants for Mother Earth News: www.motherearthnews.com/Organic-Gardening/Cover-Crops-Soil-Nutrients.aspx.