Planting Cover Crops in the Home Garden

See Recommended Cover Crops for Your Region

September 26, 2019
Crimson Clover Cover Crop

Crimson Clover Cover Crop

Pixabay

Plant cover crops in the fall to protect and nourish your soil by spring! Also called “green manure,” it’s easy to scatter the seeds. Cover crops work for any size garden—from a small raised bed to a small farm. Here’s advice and our charts on cover crops by region for the United States and Canada.

What Are Cover Crops?

Cover crops are fast-growing legumes and non-legumes that are planted for the purpose of improving soil quality and nutrition, and/or for attracting beneficial insects.

Often referred to as a “green manure” crop, it is planted in the fall after harvest and tilled under in the spring. Examples include: red clover, hairy vetch, oats, buckwheat, forage rye, Italian rye grass (sown by October), field beans and forage pea (sown by November). Cover crops literally make a living “cover” to sustain soil life until spring planting.

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Image: Cover crops mix on raised garden beds. Credit: WSU.edu

Benefits of Cover Crops

Imagine this: While you and your garden rest over the wintertime, you have a garden helper which is working hard to improve your soil! Cover crops protect existing soil, contribute organic material and nutrients to feed your soil, and keep your soil alive year-round to ensure healthy soil structure.

The numerous benefits of cover crops include:

  • Keeping soil from blowing or washing away. When you remove plants, you remove nature’s way of protecting the landscape and its fertility.
  • Increasing organic matter and nutrients
  • Increasing earthworms and beneficial microorganisms
  • Decreasing compaction and improving water, root, and air penetration of soil
  • Providing habitat and food (nectar, pollen) for beneficial insects and late-season pollinators
  • Creating an aesthetic addition to your garden during winter dormancy

An added benefit of raising cover crops is that the foliage and root growth can be tilled under in late winter to help loosen heavy soils and improve overall soil structure and fertility. 

Cover crops may be used in any size garden—from a 4’x4’ raised bed to a large farm or open field.

When Do You Plant Cover Crops?

Plant in the late summer or early fall (after harvest) in Canada and northern parts of the United States, and any time after the harvest in the southern United States.

In most regions, it’s best to plant right after harvest. The cover crops need 4 weeks before a fall frost to get established. Buckwheat can be planted earlier in areas that have already have been harvested. In the spring, you pull, cut, or till under the cover crops.

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Image: Cover crop of buckwheat in a field. Credit: Pixabay.

Which Cover Crop Should I Plant?

    These four cover crops are among the most commonly available through garden centers and mail-order catalogs:

    • Red or crimson clover (Trifolium incarnatum) is an ideal cover crop to sow in the late summer or fall and turned in in the spring in zones 6 and higher. Used as a summer legume in colder areas where it will usually winterkill. Allow it to flower and the bees will love you.
    • Hairy Vetch (Vicia villosa), a legume, is used as a cover crop to restore nitrogen to the soil for healthier plants. It grows in zones 1 to 5, and can be planted in the spring, or the fall.
    • Winter Rye (Secale cereale) is an excellent winter field cover crop because it rapidly produces a ground cover that holds soil in place against the forces of wind and water. Rye’s deep roots help prevent compaction and, because its roots are quite extensive, winter rye also has a positive effect on soil tilth. Annual in zones 3 to 11.
    • Buckwheat grows very quickly, making it a favorite “quick fix” among gardeners. It is known to grow much better in low-fertility soils. Great for suppressing weeds.

    The choice of cover crop depends on the main benefit you are hoping to obtain from the cover crop. 

    • A primary benefit in a garden is the addition of nitrogen, in which case legumes would be used. Legumes work in harmony with bacteria that lives on their roots. These bacteria take nitrogen from the air and fix it in pink root nodules, adding nitrogen to the soil in a form that plants can absorb. 
    • If you are most interested, however, in building organic matter, use oats or barley or a cereal, but remember that their incorporation will make nitrogen in the soil temporarily unavailable to the succeeding crop unless extra nitrogen is added.
    • For both nitrogen and organic matter, use a mixture of legumes and cereals.

    Many cover crops sold in the market are indeed mixes with at least one grass and one legume species. For example:

    • Rye (grass) and crimson clover (legume),
    • Hairy vetch (legume) and oats (non-legume)

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    Cover Crops for Your Region

    Of course, cover crops differ by gardening zone and region. Consult the charts below. (Click on either chart to see a larger, downloadable pdf version.)

    Click here to see full chart.

    Click here to see full chart.

    How to Plant Cover Crops

    Just scatter the seed over the area to be covered at a depth corresponding to the size of the seed. Large seeds should be covered with one-fourth to one-half inch of soil or compost. Small seeds can be left on the surface and lightly raked. Apply a thin layer of loose straw to protect the area from wind and runoff from heavy rains.

    The amount of seed to plant will vary with the species, but, in general, winter cover crops are seeded at a rate of 2 to 3 pounds per 1,000 square feet.

    Note on Inoculating Legume Seeds: If you are planting legumes as a nitrogen fixes, you also need to purchase “inoculant.” Use at a rate of at least 1 oz. per 10 lbs. of seed. To help the inoculant adhere to the seed, mix 9 parts hot water (nonchlorinated) with 1 part corn syrup (10% solution), let cool, and add a small amount of this solution to the seeds.

    Fertilizing is generally not necessary, especially for established garden beds.

    As mentioned above, some members of the legume family of plants (example: hairy vetch) actually facilitate the fixing of nitrogen into the soil, doing your fertilizing for you.Following tilling, the cover crop will decompose, and soil microbes will return nitrogen and other elements to the soil for the next crop. It is best to cut the cover crop in small pieces (i.e., shred), so it will break down faster. (For plants that have a large volume of top growth that tends to get tangled in the tiller tines, mow the tops first, then till under.)

    Once the cover crop is shredded, it is important to till the cover crop into the soil as quickly as possible. The cover crop will lose nitrogen and carbon very rapidly if left exposed in the sun. The breakdown process will take 2 to 3 weeks.

    See our video demonstrating, “How to Plant Cover Crops to Recharge Your Soil This Winter.”

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    Reader Comments

    Leave a Comment

    transplanting flowers

    Hi :) Could you please enlighten me as to what the timeline is for transplanting flowers in zone 4b? How many weeks before the 1st frost can I safely transplant a flower/bush, and for them to settle in. Thanks. Sandy

    US. Cover Crops

    I have a question that I've been unable to get 'Search' to understand or answer. I'll expand on it here.
    I reside in SE. OK. near the SW. AR. border. What would be the best Fall cover crops to sow that would be good for my largely clay soil and on which my few goats and various fowl can feed? Thanks.

    Cover Crops

    We would recommend contacting your local Cooperative Extension Service. They will know more about your area and should be able to recommend a cover crop that best suits your soil and any other needs!

    Question about Cover Crops

    Hello, my question is what do you do if you want to plant more than one kind of cover crop? I want to use cover crops to prevent weeds growing, prevent the soil from eroding, and lastly, make the soil rich in nutrients.

    Cover Crops

    The Editors's picture

    Hi Reily,

    You can plant multiple cover crops in one plot much the same as you would when planting one crop. Be careful of one outgrowing another, though. Find ones with similar or the same days to maturity. We hope this helps!

    Cover crops/gardening

    There needs to be a new region added to the planting guides - Rocky Mountain region. With our very hot, dry summers and very cold, dry winters and high altitudes, most of the advice and guides are only partially helpful. I would love professional advice from professionals familiar with our climate.

    Rocky Mtn cover crops

    The Editors's picture

    Thank you for your comments, Linda. We will try to provide some help.

    • Techniques recommended for/in Idaho may have use for you (great info here—perhaps the best of the lot, actually): http://www.extension.uidaho.edu/nutrient/culturalpractices/PDF/Cover%20Crops%20for%20High-Desert%20Farming%20Systems%20in%20Idaho.pdf

    • The Rocky Mountain Farmers Union cites “Sow True Seed” company on one of its pages (https://www.rmfu.org/farm-supplies/), with a link. (Sow True’s web pages are a little tricky; some links are “dead,” such as “About” and the information—including a lot on cover crops—appears below the “boxes”; you’ll understand when you see it.)

    • If you are in Colorado (or near) this page may be of value: https://cpw.state.co.us/Documents/CNAP/RevegetationGuide.pdf Do a search/find for “cover crop” or turn to pages 76 and 108 for information. (We did not review the entire doc.)

    ª If you are in or near Montana, experts at the State University there did extensive study on cover crops and may be able to provide guidance; see the names/emails here (at the bottom): http://landresources.montana.edu/soilfertility/covercrops.html

    • New on using radishes as cover crops: http://www.nrcs.usda.gov/Internet/FSE_PLANTMATERIALS/publications/mtpmctn12456.pdf

    • buckwheat is a traditional high-altitude cover crop (proper variety is essential): http://tcpermaculture.com/site/2014/02/05/permaculture-plants-buckwheat/

    • Barley is recommended for high altitudes here (and elsewhere): http://forages.oregonstate.edu/fi/topics/cover-crops/grasses

    We hope this helps, Linda.

    Grasshoppers

    How do you control grasshoppers for summer and then block them over the winter and hatching in the spring in michigan

    getting rid of grasshoppers

    The Editors's picture

    We looked into a number of sources about this and only one in Australia mentioned the use of cover crops—specifially, white clover, because it attracts insect predators. Buckwheat was also cited as an insectary. Perennial flowers also help to attract natural enemies. There were numerous other ideas for which we can not vouch with direct experience:

    • You could try introducing a natural fungus/organic pesticide —Nosema locustae, available as “baits,” commercially called Nolo Bait and/or Semaspore Grasshopper Control—that grasshoppers eat and which causes them to become weak and eventually die. The fatal effectiveness is about 50%, with fewer hatches the year after you use.  The percentage may vary with the amount used. Google the product names for more information.

    • Some sources recommend tilling the soil (do not forget to do fence rows and borders) in autumn to bring overwintering eggs to the surface and repeating in spring.

    • We have heard pro and con reactions to one source’s idea of using ordinary white all-purpose flour (not self-rising) to defeat grasshoppers. We have no hand’s on experience. It is said that when they feed on foliage that has been dusted with flour, their mouths gum up and they can not eat any more, become ill, and eventually die (no details on that timing). The process involves dusting plants in the morning of a heavy dew and no/little wind. Rinse the plants in two days with a light shower from a hose or the like. Repeat in a week, if necessary. Be aware that for some users the flour gummed up on their plants from rain or even the rinse.

    • Finally, keep ducks or chickens. They love grasshoppers!

    For the record, we also consulted a couple of coop extensions including yours in Michigan (as it happens, as of 2013 —the date of the post— grasshoppers were not a significant concern but see the links at the bottom of the page; if that’s not enough, you could ask Michigan again). Click through:

    From Michigan: https://ask.extension.org/questions/162757

    From Oklahoma: http://www.okrangelandswest.okstate.edu/files/wildlife%20pdfs/EPP-7196.pdf

    From Nebraska: http://cropwatch.unl.edu/emergent-winter-wheat-and-grasshoppers

    i planted red clover in the

    i planted red clover in the spring... it did great, got much taller than i expected. Need to find out what to do with it now.... let it go through the winter or dig it in now?

    Traditionally, red clover is

    Traditionally, red clover is cut twice a year when it is at 50% bloom or greater. With this harvest system farmers end up cutting too late to obtain maximum forage quality. More recently, farmers have been cutting red clover three times during the summer to get a higher quality forage. However, with a three-cut system, farmers are concerned that they may give up yield and persistence.

    http://www.uwex.edu/ces/crops/...

    http://www.forages.psu.edu/agf...