Adding sand to clay garden soil

Discussion in 'Gardening & Plant Propagation' started by Beeman, Feb 13, 2004.

  1. Beeman

    Beeman Well-Known Member

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    Our soil in this area is heavy reddish clay. We have gardened in this spot for 10 yrs. and added organic matter every year. it's better but still not what it should be. Has anyone tried tilling in sand to help break up the clay. i can get a dump truck load of sand and spread and rotovate it in.
     
  2. Aohtee

    Aohtee Well-Known Member

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    Keep adding compost. You try tilling sand into clay and you'll get conctete.
     

  3. culpeper

    culpeper Well-Known Member

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    Compost, compost and more compost. And if you haven't got enough compost, just add any dead organic material as it becomes available (like dead leaves as a mulch, some dried manure etc). It will eventually break down, and improve the soil quality. You could also toss in some clay-breaker - is it Dolomite I'm thinking of?
     
  4. Beeman

    Beeman Well-Known Member

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    Garden is 60x100', this year I've already hauled about 10 truckloads of horse barn cleanout. I have also done this with either leaves or manure every year,
    How do you get sand and clay makes concrete? I don't think the sand would make the clay bind together any better than it does already.
     
  5. Don Armstrong

    Don Armstrong In Remembrance

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    ...or, I think, any less. If you've got clay you've got clay. Add A LOT of sand and you'll eventually get sandy clay - but still clay. You'd need to start outweighing the clay by so much sand that you'd be building a mountain there, before you'd overcome the clayey nature of the soil. That's just the way clay is. Don't just take my word for it - experiment with a bucket load of your clay soil, and mix in an eighth, quarter, half, etc. bucket loads of sand.

    Like they said, humus is the way to go.
     
  6. greg273

    greg273 Well-Known Member

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    at the risk of sounding unpopular here, i would say YES, sand would help. Our soil here is something of a reddish/yellow clayey loam, which when dry is more like brick than dirt. Sand loosens the clay particles so they dont stick together quite as bad. I would say wait for the opportune moment to till it in though,when its not too wet.

    good luck,

    greg
     
  7. I'll agree with the compost crowd. Without going into everything I learned in soil sience 30 years ago it all comes down to electric charges and the structure of clay particles. Clay and compost have similar charges but different structures. Bottom line, they clump together breaking up the clay. Compost does continue to decompose while clay pretty much lasts forever so you will be adding compost for quite some time. After time you will build up a layer of planting soil comprised of humus and clay that will require less compost. What most people fail to realise is that clay soil are very, very fertile. Unfortunately the nutrients are very strongly attacked to the electrical charges of the clay particles. The Charges on the compost with attact nutrients away from the clay and as the compost decomposes the nutrients are released for use by the plants. It would be a good idea to check the pH of your soil. Clay particles are aligned like a stack of coins. This is why it drains so slowly. Adding lime will cause the clay particles to form clumps and increase its workability. Just don't add so much lime that you mess up the pH and open another can of worms.
    That reminds me, When you add your compost start adding nightcrawlers to your soil also. Again as time goes by you will be impressed. Since your garden is only 60'x100' you may want to check out double digging compost into it.
    The last thing you want to do is add sand unless you want to give up gardening and start playing tennis.
     
  8. Paquebot

    Paquebot Well-Known Member

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    Loam is the best soil that you can ever have. Look up the definition of loam in the dictionary. "A rich soil, esp. one composed of clay, sand, and some organic matter." Ideal garden mix is 75% clay-based soil, 15% sand, and 10% compost. Once you have that ratio, all you have to do is add the 10% compost annually. If you have pure clay, add 1" of sand per 6" of soil. If you are going to till a foot deep, lay on 2" of sand and 1"+ of compost. It will look like an awful lot but not when tilled that deep, which is really how deep you should till anyway!

    Martin
     
  9. Beeman

    Beeman Well-Known Member

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    Paquebot,
    That's exactly what I had read that got me thinking adding sand.
    For the person that said it's only 60x100 and to double turn it with a fork ARE YOU NUTS? I'm long past turning my garden with a fork. I'm up to 2 teactors, a TroyBilt tiller and a rotovator for the tractor. As for the compost people, how much compost do you make or how fast can you make it? We have 2 compost piles and come up with enough for raised beds and some flower beds. I have houled leaves from the town dropoff in my pickup and a trailer for years. I mean leaves, like a couple of hundred bags of them. Garden is better but still not where I think it out to be.
     
  10. Paquebot

    Paquebot Well-Known Member

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    6,000 square feet of garden is quite a lot to cover with that needed inch of compost. You almost need 10 times that much raw material. Imagine covering that area with 10" of mixed browns and greens. You're halfway home if you've got a pickup truck as no good mixed maple and oak leaves are safe from me in the fall!

    A problem with making that much compost is availability of the proper materials at the time when they are needed. I solve that by packing leaves into heavy construction cleanup bags and stacking them around the foundation of the house for insulation. This season's efforts have 56 such bags waiting for spring shredding. That's equal to at least 120 regular leaf bags. Bagged again after shredding and used as needed when grass clippings are available. That's about what it takes to cover 6,000 square feet with an inch of compost.

    The constant fallacy of clay and sand equals adobe has long been dismissed and now the only arguments are over the type of sand used. I say river sand and others will say no river or beach sand. Some say round sand and others say sharp sand. I want round river sand as my wonderful nightcrawlers like that type a lot better. Even the percentage of sand will get an argument but 15% is the accepted minimum. When I am advising on permanent garlic or potato beds, I may advise closer to 25% sand depending on exactly what type of clay is involved. The important key is combining a minimum 10% organic matter with it plus thorough mixing via tilling.

    Martin
     
  11. Beeman

    Beeman Well-Known Member

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    Paquebot,
    How do you shred your leaves? I have a Troy-Bilt shredder that doesn't work well on leaves. I use it mainly for shredding tobacco stalks which are high in nitrogen.
     
  12. JJ Grandits

    JJ Grandits Well-Known Member

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    I guess the bst way to answer the sand vs compost problem is to have Beeman put down a couple inches of sand, till it in, and report the results after the growing season. Maybe even put the garden in thirds for sand, sand/compost, and straight cmpost.
    There is one correction I'd like to point out. Loam is a mixture of clay, sand and silt, not organic matter. Although organic matter is essential for a productive soil it is not one of the components of loam. I would also like the referance that states a good garden soil is 75% clay. Is that by volume or weight? What method is used to determine if a soil is 10 or 15% sand? The same goes with organic matter.
     
  13. CrazyLadyMs

    CrazyLadyMs Member

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    are you the Beeeman that chats on Backyard Chickens? If you are then you know me. If not then now you do. haha
    I have heavy clay too, here they call it Yazoo clay. Im glad somone posted abount not using sand! I sure would have done it.

    Thanx

    Katy
     
  14. Paquebot

    Paquebot Well-Known Member

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    And I shall counter-correct the "correction"! Web definition of loam is: "a loose soil comprised of clay, sand, and organic matter, often highly fertile." First web dictionary site notes the same:

    http://www.brainydictionary.com/words/lo/loam185526.html

    Since the third ingredient mentioned is silt, look up the definition of silt. You'll find that silt is "fine particles of soil, sand, etc. suspended in or deposited by water."

    Now for the method of shredding leaves. I twice burned out motors on Flowtrons before the company informed me that their contraption was not designed for prolonged use. Prior to that, I simply set up a backstop of two sheets of plywood and went over everything twice with a lawnmower. Went back to that after the Flowtron fiasco until a friend came up with a Merry Mack chipper-shredder. Short production little cousin of the commercial Mighty Mack. Not nearly as efficient as Troy Bilt or similar. It handled the 50+ bags last year at one go and one tank of gas. Doesn't like damp leaves but did a number on the dry ones with no problem. Personally, I prefer the mower as it can also handle any damp leaves plus whatever greens may be available at the time. I also sharpen my mower blade right to the center hole for a more thorough chopping job. "Corn flakes" after the first pass, "oatmeal" after the second!

    And how can one tell what percentage of sand and clay make up your soil? Water! Take a pint of soil and a pint of water. Mix them thoroughly in a quart jar. Then let it all settle. Bottom layer will be your sand. Clay will be in the middle. Any silt and organic material will be the top layer.

    Martin
     
  15. Sand is porous and will suck the water out of the clay, making the clay stick to it. I agree with The Compost Gang. Sand and clay does make adobe.

    LL
     
  16. poppy

    poppy Guest

    Maybe different clays matter, but we have heavy yellow clay. You can't dig a hole to plant a flower when it is dry. After we moved here, we tried to garden in it for about 5 years just adding what compost we had. Never made much difference. Then I put a dumptruck load of sand on about an area of 30 by60 and worked it in. Made all the difference. Now it stays loose and productive. Too much sand will dry out pretty quicky, so you'll need to water. Sand is a very good growing medium if you can keep it moist. About 6 miles from here, we have an area called sand ridge, pretty much pure sand. Some of the best farm ground around and they grow a lot of melons there as well as corn.
     
  17. sbeerman

    sbeerman Well-Known Member

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    Hi beeman ,
    This is the best explanation of adding sand to clay that I've seen to date.
    http://forums2.gardenweb.com/forums/load/soil/msg0109383521338.html
    Look for the 16 post down "Posted by: shrubs_n_bulbs z8/9 UK "
    I lived where we had clay soil, and knowing there was no way I could buy enough "Sharp Sand" to improve the clay with out really messing it up I would but one 10 yard load of sharp sand a year, $80.00 a truck load this was my Mothers Day Presant for years. What I did was amend the " whole " that I was planting my transplants in.
    I used about 1/3 soil, 1/3 compost, 1/3 sharp sand figured I felt better because I was trying to improve soil but probally would't be ruining it either.
    Happy Gardening Sandie Or.zone 6/7
     
  18. Martin, I'm sorry if I said something wrong. I read some of the posts and answered as I thought was correct. Like the man said, I suppose it depends on what kind of clay it is. He says he has that old hard yellow clay and that is what they make adobe out of. Please accept my apology if I did something wrong, but this happened to me at the house I used to live in. I had the same stuff and it wouldn't even grow grass. The only thing that would grow out of it were dandelions and weeds, even when I added sand and compost. The ground was so hard that whatever I tilled just washed away. It couldn't sink in.

    Mea Culpa, sir.
     
  19. Interesting subject, since it applies to some of my garden failures I did some looking and found what may be the reason for the divergences of opinions posted above, see Dr. Chalker-Scott article below.

    “Our soil in this area is heavy reddish clay. We have gardened in this spot for 10 yrs. and added organic matter every year. it's better but still not what it should be.”

    As to trying to improve your soil with organic matter (I've been this also and expecting better soil), it seems that the organic matter only helps for about 6mos or so, due in part to the plants taking it out of the soil, so this is not a long term solution to the clay problem, sort of the possiblity of a massive amendment/input of organic material.

    “Has anyone tried tilling in sand to help break up the clay. i can get a dump truck load of sand and spread and rotovate it in.”

    The “Question” of contention and difference of opinion appears to be, how much, if any, sand to add to clay to make it better. After looking at several authoritative (Univ. based types) articles it appears that there is no real consensus as to the “Best” solution.

    Though it seems pretty straight forward that too little sand will make the situation worse, like the “cement analogy” mentioned above and referred and explained in the article below.

    So when you go about mixing in sand, you will know that you need more if the situation gets worse (like cement soil) and you can somewhat safely know that it will get better if you continue to add more sand, the question is how much to add and what will the cost be.

    Don seems to have hit it right on the head, experiment with various percentages of each, see what it will take to get your clay soil to the point that you are happy with it.

    Hope this helps.

    http://216.239.39.104/custom?q=cach.../amend2.pdf+amending+clay+soil&hl=en&ie=UTF-8
    Dr. Linda Chalker-Scott, Associate Professor,
    Center for Urban Horticulture, University of Washington
    The Myth of Soil Amendments Part II:

    “Soil texture
    Soil texture is determined by particle size, which ranges from microscopic clay flakes to more rounded silt particles to sand grains. While undisturbed sandy soils are well aerated and well drained, they are nutrient poor since sand and silt cannot bind mineral nutrients. In contrast, clay soils do bind mineral nutrients but have poor drainage and aeration. Thus, a soil with both sandy and clay characteristics should be optimal for plant root health. So it's easy to see how the practice of adding sand to clay soils has evolved.

    The problems occur when sand and clay are mixed in incorrect proportions. An ideal soil has 50% pore space (with the remainder consisting of minerals and organic matter). The pore spaces in a clay soil are all small, while those in a sandy soil are all large. When one mixes a sandy and a clay soil together, the large pore spaces of the sandy soil are filled with the smaller clay particles. This results in a heavier, denser soil with less total pore space than either the sandy or the clay soil alone. (A good analogy is the manufacture of concrete, which entails mixing sand with cement - a fine particle substance. The results are obvious.)

    A soil must consist of nearly 50% sand by total volume before it takes on the characteristics of a sandy soil.

    For most sites, it would be prohibitively expensive to remove half the existing soil and add an equal volume of sand and then till it to the necessary 18-24". Mineral amendments of large particle size, such as perlite, may provide some benefit but can also be costly depending on the size of the site. (Reducing this task to amending only the planting hole is a recipe for plant failure and perhaps will be addressed in a separate column.)

    Soil structure
    Soil structure is the next level of organization for soil particles. Sandy and silty soils don't have much structure (and these soil qualities are primarily determined by particle size). Soils with more clay content, such as the various loams, aggregate into larger chunks called peds. Highly aggregated soils are optimal for root growth and aeration, but can be easily destroyed by any activity that results in soil compaction.

    Soil structure can be improved through proper site preparation and management. One of the least invasive and most cost-effective ways to do this is by the use of organic mulches. This is especially effective for landscapes that receive high volume foot traffic. My landscape restoration classes now routinely have wood chips spread on site to allow soil recovery to begin as they prepare the site and install new plants. One particular site, a small lot near a bus stop, consisted of weeds, bare soil, and a few existing trees and shrubs. When we tried to take a soil core, the corer bent! We had 8-10" of wood chips spread over the whole site as we began our work. A month later, we moved aside part of the mulch and dug out a shovelful of rich, loamy soil. Had I not seen it for myself, I'm not sure I would have believed these stunning results. The addition of the wood chips allowed the site to retain soil moisture and reduced the constant impact from foot traffic, thus enabling the soil to regain its structure.
    Bottom line:
    • Clay soils are not inherently bad, but can be problematic if they lack good structure.
    • To significantly alter a clay soil, sand must be incorporated to about 50% of the total soil volume.
    • Many problems associated with clay soils (poor aeration, drainage, etc.) can be alleviated through good management practices.
     
  20. Bill in Tn

    Bill in Tn Active Member

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    When we retired to Middle Tennessee, one of the first things I did was have a 40'x75' spot of sod tilled up for our garden. The soil looked great, and I couldn't wait to plant. Then it rained, and it turned into what appeared to be red cement. I couldn't drive a spade into it. So I hauled in enough cow manure to spread about 3 or 4 inchs thick, had it tilled again and planted. I had beautiful plants, but the ground was still hard. I then had a truck load of sand delivered and mulched the entire garden at least 2 inches deep. That kept the weeds down all season. That fall I added another couple inches of horse manure and tilled it all in. Turned out great. I can now sink a spade anywhere in the garden at anytime even after a dry spell. Worked for me. Bill