Cover Crops-whats the deal

Discussion in 'Fruit and Vegetable Gardening' started by stihlman, Feb 7, 2007.

  1. stihlman

    stihlman Member

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    I'm not sure if i understant these cover crops. From what i have read cover crops are great for adding nutrients to the garden-i can understand that but which one,fall rye,buckwheat,alfalfa? Sound to me whichever is used i wood broadcast the seeds in early fall after garden is all done then rototill in spring(when-2weeks before i want to plant so it will drown out all other weeds)
    Which brings me to the next question. What i've been reading about cover crops is that they are used to keep weeds down-How? Do you broadcast seeds after your vegetables are established in early summer?
    Any info would help.
     
  2. biggam

    biggam Active Member

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    Cover crops have a variety of benefits and uses; I will touch on a few. Generally they are growing in the "off" time, although there are some that are interseeded, such as red clover in corn. A large vegetable field, for instance, might be seeded with rye at the end of the season and is plowed under in the spring (yes, 2 weeks before sowing or transplanting your crop plants). This prevents erosion, leaching of nutrients, and reduces germination of "winter annual" weeds. Rye will have a fair amount of carbon and break-down slowly, so nutrient addition is negligible (it can actually tie-up nitrogen, while mustard or buckwheat, for examples, will break-down quickly and not tie-up nitrogen); although, for the long-term, soil health & fertility is enhanced due to the addition of organic matter and the scavenging of nutrients. Buckwheat grows fast and provides dense shade over the soil, preventing weed germination and growth. Buckwheat is efficient at taking up phosphorous from the soil, so plowing it under tends to make more phosphorous available for proceding crops. Legumes are used to enrich nitrogen content of the soil. Oilseed radish can combat pathogens in the soil as well as inhibit weed seeds; this happens as the plant releases chemicals as it breaks down. Millet and Sorghum-sudangrass smother weeds, and there are many other cover crops. Another benefit could be that beneficial insects are harbored on the plants. Some, like rye, will survive winter and grow in the spring, while others will winter-kill, and still others are sown in the spring. Most of the information you find will pertain to fields and orchards, but the concepts could be applied to smaller spaces. Usually these crops are killed when they are in flower. If you let them set seeds, these could potentially become weeds themselves; in other cases, maybe you wouldn't mind if they reseeded themselves. I had some crimson clover growing under a young tree last year that a rabbit kept from setting seed (or even flowering,) then winter temperatures must have killed them in the last couple months. I'll probably experiment with buckwheat and mustard next year. Fedco Organic Growers Supply has some seeds, and their website can be found through Google.

    Here is a website with more info and links about cover crops.

    One last use I'll mention is in no-till systems. I participated in a study last year growing pickling cucumber in conventional, strip-till, and no-till treatments. There was also an herbicide factor of either none applied, half-rate applied, and full-rate applied; I'm not sure which chemical it was, but it was just one application, shortly after seeding the cukes. Half of the field had rye (sown in fall) and the other half had oats (sown early spring I believe). Rye & oats were killed in the spring with glyphosate. To get to the point -- the best yield was in the no-till oats, and the half-rate herbicide was practically as good as the full-rate. The lack of exposing the soil to light (which happens during tilling or cultivating,) meant fewer germinating weeds, and the grass (oat or rye) residue also shaded-out weeds and helped keep moisture in the soil for the cucumber plants. The rye had gotten so tall that it also shaded-out many cuke seedlings, but it might have worked well if we were growing pumpkins rather than cukes.
     
    Last edited: Feb 11, 2007
  3. stihlman

    stihlman Member

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    So Biggam your knowledge sounds to be pretty extensive of this subject. Let me break down my situation a little more, i have just started gardening 3 years ago and have an area of about 45'x75' that i plant all the regular veggies in(tomatoes,peppers,squash,onions,leeks,etc.) the other plot is about 90'x175' that i already have a couple rows of assparagus in and plan in the future(1-2 years) putting all my fruits and berries in. In the mean time i will be adding manure and compost to it so i can enrich the soil. I'm trying to stay organic as i can and all that i grow is for me and wife and give the rest away. We seem to have very good luck with growing, so we really like what we are doing. Anyway, sounds like if i where to plant buckwheat one year and oilseed radish the next and then throw fall rye in the 3rd year and keep rotating, this would be good?
    It seems like cover crops are easy-broadcast seed-let grow-rototill-boom,very little effort and you gave nutrients and kept weeds down and out of the 2, weeds are more important to me as i don't mind spending the money for great compost to add nutrients.
    Hope you can give me some more insight!
     
  4. Durgan

    Durgan Contributor 10 Years

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    http://xrl.us/rzba

    The garden is planted in red clover (annual) as crops are removed. I find in my area Zone 5 that the latest to plant is about the end of September. The clover is allowed to grow until spring, when I cut any that remains with a weed wacker or lawnmower after the winter freezing cycle, then rototilled well into the soil.

    My view of using clover is that it feeds the earthworms and supplies some nutrients, which may be a plus, but I get plenty of fine compost from the city each year, so this is not a big issue with me. I like the idea that it adds some fibre to the soil, and I am of the opinion that no ground should be left fallow-for no good reason.

    The last picture of the link shows the garden with some clover growing, which was seeded at differnet times, hence the different heights.

    White clover is a no-no, since it is hard to eradicate due to growing from the roots. Red clove is propagated from the seeds only. I made an error once and pulled white clover all summer from amongst my vegetable crops.

    Durgan.
     
  5. biggam

    biggam Active Member

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    Grow cover crops for a year first in an area to be established. Prepare ground and sow oilseed radish (or other mustard) in spring. Rototil this when in flower. In mid-August (or about 5 weeks before first killing frost) rototil any weeds that have come up and sow buckwheat. The weather will kill the buckwheat before it sets seed; this can be incorporated in spring, or potentially could be planted into as a no-till option (which would really lessen weed pressure), depending on what is being planted.

    Subsequent years sow cereal rye in late fall as a cover crop, with the option of mixing in oilseed radish together with the rye.

    You could do the radish/buckwheat in half your vege plot and see what a difference there is in weed pressure the following year. Some of the radish or mustard greens could be harvested and eaten too.

    Here is something about growing rye in asparagus that may be of interest.
     
    Last edited: Feb 9, 2007

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