September is getting on and most gardens are tapering off. As for mine, potatoes and onions are tucked in the root cellar, tomatoes in every form line the shelves in the pantry, okra and corn are frozen. I only have yet to contend with a few lingering tomatoes and a row of carrots. It has been a good year and I am thinking of trying something completely different to make the garden even more productive next year. Instead of just letting it lay idle during the winter months, a cover crop can help a garden as much as it does farmers’ fields.
What exactly is a cover crop? Basically, it is any number of different crops planted primarily to manage soil erosion, soil fertility, soil quality water, weeds and pests. These crops are also known as green manure. They are easy to plant and require only basic care.
It’s not just what goes on above ground that counts but also what happens with the roots underground. Having a root system in place, as opposed to bare ground, helps retain soil from erosion and helps compaction which is the process of removing voids in the soil to increase density and the load-bearing capacity.
A cover crop does exactly what its name implies, it covers the ground. Thus, weeds have a harder time gaining a strong hold. Cover crops can also return vital nutrients back to the soil. Farmers, and gardeners, can rely on nitrogen from cover crops to grow next season’s crop, rather than spending money to purchase traditional fertilizer. Heavy vetch and red clover can actually “fix nitrogen” which means they take nitrogen from the atmosphere and put it in the soil.
Gardens take a beating. Tilling, weeding, harvesting and just regular foot traffic tend to destroy soil structure. Much of a garden’s space is “wasted” during the off season anyway so it just makes sense to plant something that will provide a number of advantages when it is worked into the soil in the spring.
Grasses are easier to grow than legumes like clover because they germinate more quickly and are easier to start in poorly drained areas. Winter rye and ryegrass are good at shading out weeds. Annual ryegrass , oats and buckwheat do not overwinter but are easiest to work with in the spring since the tops have died back.
These are decisions and more decisions for gardeners. How do you know what type of cover crop is best for your soil? It all depends on what you are trying to accomplish. Decide if you are going for weed or pest control, adding nutrients or trying to stop erosion. Then choose a variety of cover crop that has the characteristics that suit your needs. Here are a few of the top ones for gardens:
• Annual ryegrass is a popular choice for a garden cover crop. It is a vigorous grower with an extensive root system that occupies the same root zone as garden plants. It does winter kill which means you are able to plant your garden earlier since you won’t have to turn the soil and wait three weeks like a perennial crop.
• Sorghum-sudangrass. This type of cover is a cross between the two. This hybrid generates a large amount of organic matter, literally it needs little encouragement to grow to heights of 5 to 12 feet. It adds a ton of nutrients but definitely needs to be kept in check. This can be done by planting 7 weeks before frost or by mowing it down to a height of 6 inches when it reaches 3 feet tall.
• Buckwheat. No, this is not a variety of wheat at all, nor is it a Little Rascals character, but rather it is a well-rounded cover crop. It is fast growing , making a quick canopy to shade weeds which makes it an excellent smother crop against weeds like quackgrass. Another one of its perks is that it works well as a filler for flower arrangements and attracts beneficial insects. It also matures in 6 to 8 weeks so you can squeeze it in between spring and fall plantings. The downside is if it goes to seed you are sure to have buckwheat in next year’s crop.
• Clover. This is a plethora of different shapes, sizes and colors. Yellow blossom sweet clover is an excellent nutrient scavenger, helping to build good soil structure. White Dutch clover works well as living mulch because it tolerates shade and traffic. Crimson clover attracts beneficial insects and looks great too. Whatever color, clover fixes nitrogen and helps build rich soils.
• Field Peas/oats. These two, when combined, gives the gardener the benefits of a legume (peas) that fixes nitrogen and a grain (oats) that contributes plenty of organic matter. They are both cold-tolerant, which makes them a good mixture for late summer, early fall. In colder climates they both winterkill, allowing for an early spring start. A final plus for them is they have complimentary growth habits, peas climb up the oats.
As many benefits that cover crops offer, the one drawback for gardeners is that they pay premiums for seed in small packages rather than the farmer’s bulk seed prices. Be sure and check your local farm supply store for seed. They may be willing to order varieties that they don’t normally carry that also can offer a price break.
Cover crops may be the hardest working plants that you will ever grow. Most folks are pretty partial to making their gardens the best they can be. One final effort at the end of the growing season can make a big difference in next year’s garden. Cover crops can give the savvy gardener that edge.