How to Grow Cover Crops to Improve Your Garden Soil

Used in farming for years, you can also grow cover crops in your home garden to improve and protect the soil. The recommended seed sowing times are early spring and fall but there are a few things to consider first.

You will find more tips like this in the Empress of Dirt Fall Garden Checklist.

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Getting Started with Cover Crops in the Home Garden

Before we get into options for cover crops, let’s have a little reality check. I see a lot of information touting cover crops as an incredible solution for a range of garden problems. But, from everything I can find, the claims are far too generalized and exaggerated. Yes, cover crops have some value—like many soil amendments—but rumors of their superpowers are greatly exaggerated.

How effective cover crops will be for your garden will depend on your soil and growing conditions, the crops you choose, and how you manage them. Left unmanaged, these plants can take over your garden.

In addition to first getting a detailed soil test from an accredited lab to understand what your soil actually needs (or doesn’t), keep in mind that using cover crops in a home garden is basically equivalent to applying a good manure or compost to the surface of your soil.

In other words, it’s another way to add organic matter that will gradually integrate with the existing soil. They can also help prevent soil erosion in fallow areas.

But, unlike other top-dressings, deep-rooted cover crops in particular may require some deep digging which can be disruptive to existing soil structures including microbial eco-systems. There are, however, shallow-rooted alternatives if you are wary of double-digging and want to minimize this.

So, think of cover crops as another possible option for your garden that require some research ahead of time.

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Contents

• What Are Cover Crops?
• How Are Cover Crops Used?
• Benefits
• Drawbacks
• Seed Options | Legumes, Grains & Grasses, Brassicas

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What Are Cover Crops?

Cover crops go by several names including green crops, fodder crops, green mulch, and green manure, but no matter what they are called, the goal is to grow a temporary crop that protects and/or enriches your garden soil.

When a growing space is left fallow with bare soil, weeds take over and wind and rain can carry precious topsoil away.

Years ago farmers started planting cover crops both to protect the soil between fall harvest and spring seed sowing time and restore lost nutrients.

While traditional cover crop advice is suited to agricultural settings with specific needs and heavy equipment to employ—stuff we don’t have at home—there are opportunities to do something similar on a smaller scale with more suitable plant choices that we can manage by hand.

How are Cover Crops Used?

Cover crop seeds are sown in the off-season, generally after fall harvest so they will be ready to integrate into the soil in early spring. These may be annual or perennial legumes, grains (like rye and wheat), or grasses that suit your location, climate, timing, and soil needs.

As the cover crops begin flowering, marking peak nutritional value (before seed production starts), the plants are pulled out or chopped down (to halt growth) and left in place where they can decompose, gradually contributing nutrients and structure to the soil. It’s essentially compost you grow in place. Leguminous types (see section 1, below) also fix nutrogen in the soil.

What are the Benefits of Cover Crops?

Again, this will entirely depend on your soil conditions and what you grow, but here are some possible benefits.

• Stability | While growing, cover crops can prevent bare soil from blowing or washing away. This alone may make it worthwhile if your garden is prone to seasonal flooding or heavy winds.
• Organic | While it’s difficult to know if mulch and compost we purchase are herbicide-free, it is possible to source organic cover crop seed.
• Winter Wildlife Habitat | Over the winter, cover crops—like other garden plants—provide habitat for creatures great and small including birds, countless insects and microorganisms and other wildlife.
• Outcompete Weeds | When planted densely, cover crops may outcompete weeds. In my experience weeds almost always win, but theoretically this is possible depending on your weeds and choice of crops.
• Aerate Soil | Deep-rooted cover crops can help aerate compact soil and improve drainage (but, on the downside, may require extensive digging to remove).
• Add Organic Matter | Ultimately, when turned into the soil, the crops provide new organic matter: what and how much—and how soon—depends entirely on what you’ve planted and your conditions.
• Reduce Pests & Diseases | Anecdotally, gardeners report they can also stop pest and disease cycles with cover crops, resulting in greater future yields. That’s a big statement that is too broad to substantiate, but there may be specific instances where this could be true. You’d have to research it on a plant-by-plant basis for more information.

Are There Any Drawbacks to Using Cover Crops?

There could be. Here are a few things to consider.

First of all, we know adding organic matter to the soil is enriching—if the soil needs it, but how effective cover crops are is impossible to quantify.

First, does your soil need it? Get a soil test and use that to determine your soil amendments.

Is it better than adding manure or compost? Probably not: it’s just another way of doing the same thing.

But, if you are trying to fight winter soil erosion, those roots could really help hold your soil in place.

Another drawback, as mentioned, is some cover crops may require deep digging or pulling to stop their growth and add them to the soil.

If you’re a no-dig gardener like I am, you’ll want to look for shallow-rooted cover crop options like buckwheat so there is minimal disruption to the existing soil ecosystem.

Also, the key is to always remove these crops before they go to seed—otherwise the whole thing backfires because you’ve got self-seeding crops when you don’t want them.

And finally, not all crops decompose at the same rate: some breakdown rapidly while others may take years so any benefits gained may take several seasons to take hold.

Cover Crop Seed Options

Before you get cover crop seeds, decide what it is you want them to accomplish. The seeds sellers (below) provide a lot of information to help steer the decision.

There are hundreds of choices for cover crops including annuals and perennials. Some like full sun, others tolerate shade.

And keep in mind that you can combine crops as well, to address multiple needs. Some sellers have pea and oat combination mixes for this reason.

Read your seed packets for amounts to use. Also, sowing time will be fall or late winter or early spring, depending on your seed selection and zone.

1Legumes

Plants in the family Fabaceae including beans, peas, clover, and vetch.

These are known as the nitrogen fixers, helping convert nitrogen into a form that plants can use.

• Alfalfa Medicago sativa | Perennial
• Alsike Clover Trifolium hybridum (hardy to zone 3)
  This one tolerates clay soil and flood conditions. Can be toxic for horses.
• Bees in Clover (blend of Ladina, Medium Red, Alsike, and Crimson plus Annual Ryegrass)
• Crimson Clover Trifolium incarnatum | Hardy annual down to zone 6. Buy it here at Seedsnow.com
• Ladino Clover Trifolium repens
• Medium Red Clover Trifolium pratense | Short-lived perennial down to zone 4.
• White Dutch Clover Trifolium repens (perennial down to zone 4) | Shade-tolerant. Buy it here at Seedsnow.com This is best used as a perennial, living mulch that you mow down several times a year.
• Yellow Sweet Clover Melilotus officinalis. | Biennial.
• Fava beans Vicia faba | Annual. Buy it here at Botanical Interests
• Spring Field Peas Pisum sativum | Fast-growing annual – do not follow this crop with another legume.
• Winter Field Peas Pisum sativum | Fast-growing annual.

2Grains and Grasses

Including oats, barley, wheat, and rye.

These are often used to protect the soil, while the legumes are used for nitrogen.

• Barley Hordeum vulgare | Fast-growing annual with deep, fibrous roots.
• Buckwheat Fagopyrum esculentum | Hardy annual.
  A top pick for cover crops: fast-growing, attracts pollinators and several beneficial predatory insects. Buy it here at Seedsnow.com
• Chickpeas Cicer arietinum. 
• Fall & Winter Rye Secale cereale | Fast-growing, said to Inhibit weeds. Buy it here at Seedsnow.com
• Winter Rye | Fast-growing.
• Oats Avena sativa | Recommended to sow with clover or vetch. Hardy to zone 8.Buy Pea and Oat Mix at Botanical Interests
• Winter Wheat Triticum sp. | Hardy to zone 3.
• Annual Ryegrass | Lolium multiflorum | Deep-rooted hardy annual (zone 6).
• Perennial Ryegrass | Lolium perenne | Fast-growing, tough grass.
• Triticale x Triticosecale | A hybrid of wheat and rye.
• Hairy Vetch Vicia villosa | Deep-rooted hardy annual. Seeds are toxic to chickens. Buy it here at Seedsnow.com

3Brassicas

There is one commonly used cover crop from the Brassica family:

• White Mustard Sinapis alba | Fast-growing annual fast-growing annual with disease-fighting properties.

If you try some cover crops, I’d love to hear which ones you chose and how they did.

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~Melissa the Empress of Dirt ♛