This is a great natural farming technique to help reduce the need for fertilizers, pesticides, excessive watering and more. This is a technique you can use for any number of applications. Let’s discuss what it is first.
Cover crops are simply densely planted species of weed, herb, flower, or vegetable that are used not for themselves but in the aid of another plant. For example, if you are growing vines in a vineyard, you might plant common vetch to keep the weeds between rows under control and conserve moisture in the ground. Another grower might use a cover crop with deep tough tap roots, like alfalfa, to break up clayish soil and introduce organic matter/nutrients subsurface. Yet another gardener might plant a cover crop of flowers to attract beneficial pollinators to their orchard.
The basic idea is simple: use plants (cover crop) to achieve whatever you need to make your garden flourish. What an interesting, simple way to achieve your garden goals. This is a quintessential “natural farming technique” and I just love it.
What to use cover crops for
There are a myriad ways to use cover crops to achieve your goals. When used correctly, they can be beneficial in almost any way you can imagine. Let’s look at some of them:
Protect soil from erosion – like all plants, the roots will help bind soil and keep it from eroding
Regulate plant growth – can add or take away nutrients depending on what you need
Improve soil fertility – improve soils ability to hold nutrients
Enhance biological diversity of the soil – both during growth and as they decompose, they attract microbes
Draw large predators away – attract birds to cover crop rather than main crop
Improves soil base – no more soft muddy ground during rain storms
Improves soil structure – helps aggregate soils, both during growth and through decomposition
Pollinate crops – attract pollinators to the area, will improve pollination of main crop also
Provide habitat – for both beneficial insects and pest predators
Rejuvenate depleted soil – plant between seasons to replenish soil nutrients
Improve air/water quality – keeps dust out of air, locks nutrients so you don’t get nutrient runoff in water, etc
Those are just some of the ways cover crops can be used to enhance your garden ecosystem. Just some!
How to cover crop
Well this is very simple to explain (just plant the cover crop, that’s how you do it, duh) and very complex because it all depends what kind of results you want, what kind of setup you have, what can grow in your area, etc. Many factors vary depending on the cover crop you pick. These factors include when to plant, if and when to cut down, how to cut down, how to manage the cover crop and how soon after is ok to plant.
Here is a list of some benefits you might need and possible cover crops for that purpose:
Goal Plant Types to Use
Fertilize soil, add NitrogenLegumes: cowpeas, soybeans, sweet clover, vetch, sesbania, velvet beans, sunn hemp
Control weedsSudangrass, millet, sorghum, buckwheat, crimson clover, hairy vetch, oats, rye
Forage for animalsMangels, millet, rape seed, turnip, oats, rye
Attract pollinatorsBorage, alfalfa, buckwheat, many clovers, many vetch, fava bean, sunflower
Break up compacted soilAlfalfa, mammoth red clover, daikon radish, yellow sweet clover
Protect from soil erosionFast-growing and over-wintering crops like winter wheat, crimson clover, hairy vetch
Conserve soil moistureGrasstype crops: rye, wheat, sorghum-sudangrass hybrid, medic and indianhead lentils
Just like most things in gardening, variety is king. Mix and match cover crops to multiply their benefits. Choose a deep-rooted tall crop with a surface cover crop, or a heavy flowering crop with a grass, or some other combination.
Here are some great cover crop combinations:
Peas(cowpea or winter pea) and radishes (daikon radish): peas provide nitrogen so radishes grow deep roots and grow tall so peas can climb them. Break up hard soil and add lots of nitrogen.
Grass-legume combo (hairy vetch/red clover + winter rye, bell beans + oats, etc): Many benefits including better soil cover, better decomposition (carbon-nitrogen ratio), enhanced growth (more mulch later)
Rye, hairy vetch, crimson clover, winter peas: winter annual cover crops to be mowed after flower in spring
There is a great page here from the Rodale institute with information on common cover crop species. The charts there are awesome and you might check that out when considering species to plant.
Now that you have selected your cover crop species, it’s time to plant. Planting is a big topic and really depends on the crop varieties you have selected and your goals. For example, you might have an apple tree orchard you’d like to attract bees to for pollination. You might choose a fast flowering plant like buckwheat and plant around a month before the apple trees bloom. The cover crop blooming the same time as the apple trees helps attract pollinators to the orchard. If planting a fertilizer cover crop, you might choose a hardy winter crop, plant in fall when the garden is finished, and mow down in the spring just after the cover crop flowers.
Harvesting your cover crop is another big topic that depends on the varieties you have chosen and your goals. Here are two main factors:
Timing: Some cover cropping strategies won’t need mowing at all. They will reseed themselves and come back each year. Others will be perennials you cut every two years at the height of their maturity. Some cover crops will be cut right before you plant the cash crop while others will be planted to grow or bloom at the same time. Think about your goals for the cover crop, and when/how you harvest will follow.
Method of cutting: Some cover crops are designed to be mown down. But if you’re using the cover crop for fertilizer/nutrients, you’ll want to “turn under” the cover crop – get the green manure covered so it composts without UV exposure so the soil gets maximum benefit. Another method is to “roll” the cover crop – basically just roll over the crop so all the stalks break and it forms a nice thick mulch as it dies and decomposes on the surface.
Now you’ve chosen your cover crop, planted it, and harvested it for the benefit of your garden. What a great way to use nature! I hope this introduction has inspired you to try this excellent natural farming technique in your own garden!