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sharp/coarse sand to amend clay

Posted by joeschmoe 6 (Ohio) (My Page) on
Wed, Dec 26, 12 at 8:32

Although I've been convinced that organic matter is the best way to amend clay, I have also seen people use sharp sand (NOT play sand or fine-textured) to amend clay and make it better draining.

If I were to do so over a specific area, how much would I want as a depth or percentage, assuming my tiller can go about 8" deep (on the second pass)?

The idea is that I am planting a few things that need very well drained soil. I have an area of the yard that already sits slightly higher than the rest, so I figured if I want to build it up a bit higher, I can either bring in "topsoil" (something I get nervous about, since you never know what you'll really get), or, amend it and add volume, which sand would of course do.

My soil actually tests out as a "clay loam" (almost an even amount of silt, sand, and clay, actually) so it's not THAT bad, nothing like what I've seen other places but still "mucks up" when wet and gets pretty hard when it's dry.

Finally, if I were to do this, what do I need to specify to make sure I get washed/salt-free sand? I don't want to find out I have unwashed ocean sand! I don't even know where most Ohio suppliers get their sand, it may well be from freshwater lakes instead.


Follow-Up Postings:

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RE: sharp/coarse sand to amend clay

Sand won't help clay and can make things worse even while too little wastes your time, effort and dollar$. To be helpful, the final sand content needs to be about 60 percent by volume.


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RE: sharp/coarse sand to amend clay

Use can use decomposed granite as a rock/mineral component which is usually relatively inexpensive. The soil mix that Jon Hughes uses works great in his Oregon climate - ~25% each of native clay, compost, decomposed granite, and pumice. There are many good amendments you can add. Some say to avoid sand for amending clay soil since it doesn't add much in terms of nutrients and somewhere around 1/2 by volume must be added for the sand to improve soil structure and drainage, while others have good experience with sharp/coarse sand. Compost is pretty much always good, as much as you can get, to improve soil structure and nutrition. It depends on what kind of soil you have now and what is readily available to you. For smaller or raised beds you can make a premium mix like the one above, or for larger areas you might consider spreading many loads of any manure available, compost, working it in, and cover crops.

Here is a link that might be useful: Jon Hughes garden videos


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RE: sharp/coarse sand to amend clay

The type of clay you have can greatly effect your amending when it comes to clay.

Many red and/or hard clays can make crusty bricks with sand amendment...some grey and sticky clays can handle sand amending without too much negative effect.

I'm still a fan of topsoil, compost, and organic amendments for clays of any type. Topsoil tends to be the cheapest, adds a bit to the nutrient profile, and tends to disperse clays rather than sticking to them.

Sand in heaving-type clays that expand/swell can be pushed up in the profile over time negating some of the effects of incorporation, too.

Also, clay is awesome stuff that gets a bad rap. It needs other types of aggregates mixed in for best effect, but it's a natural moisture and nutrient trap that can help you "feed" and water your soil less often.


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RE: sharp/coarse sand to amend clay

Since the original poster is from Ohio, I probably have the closest soil to that with my clay/loam and I am not far from silt/loam soil.

I have added 3 inches of local pit run screened sand that makes it a medium/coarse sand. I don't add just sand though. At the same time I added 4 inches of local sphagnum peat moss. As soon as it all was mixed well together in medium moisture conditions, it was wonderfully loose and has been ever since. I believe that smaller amounts of those two amendments would work to a degree too. I have seen absolutely no bad effects.

These amendments are long term texture changes. The sand does not feed the soil and plants, and the peat moss does some, but that isn't the purpose of it. I add organic material and some minerals for that.


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RE: sharp/coarse sand to amend clay

here's what I would do...

as much as possible, I would localize the plants that want better drainage and dig a few holes with a fence post auger as deep as you can, then fill those holes with larger rock and debris, like 2-4", and the more irregular the shape, the better. Then put a few inches of planting mix and plant.

or use berms.


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RE: sharp/coarse sand to amend clay

I would try the sand if it were me, since your soil is clay loam. I would also use compost. Water availability tilth, and drainage are you problems with clay soil and compost would help with those. Sand might help with drainage and tilth. Alternatively you could also just use raised beds and put whatever materials in them you want.


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RE: sharp/coarse sand to amend clay

Cornell says to make any difference by adding sand to your clay you would need to add 75 percent sand. Numerous other universities will tell you (I think Ohio State is one) that you would need to add 45 percent sand to clay. The same thing applies to expanded shale or any other mineeral soil amendment, very large quantities are needed to make small differences.
A fairly small amount of organic matter, considerably less then the mineral soil amendments, will do a much better job. On our way to Columbus this past week I saw many fields sitting there totally exposed to the the weather so what soil is there could easily be eroded by the wind. Many of the fields I saw had standing water on them indicating a drainage problem. A few appeared to have been planted to winter wheat, or maybe Cereal Rye (difficult to tell as you go by at 65 mph), but not all.
Add organic matter to your clay, not sand.


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RE: sharp/coarse sand to amend clay

I don't have just plain clay soil, and I doubt that few here do either. Clay loam by definition has about 30% sand already. So you DO NOT need 70 % more sand...goodness!


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RE: sharp/coarse sand to amend clay

I agree Wayne 5! Clay loam, according to the soil triangle used to classify soil texture, should have 60-70% silt, 20-45% sand and 30-40% clay. Adding sand may improve your drainage to some extent, however the soil underneath your sand amendment will still retard water drainage to some extent. Joeschmo I would trade you soils in a second! I have loamy fine sand which is excessivly well drained. Adding sand would probably give you a sandy clay loam or a Sandy clay depending on how much silt you have. Here is a link that may help, which shows the soil texture triangle: http://www.soilsensor.com/soiltypes.aspx


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RE: sharp/coarse sand to amend clay

Here's a Soil Triangle that should help you determine how much sand you want to add. This a borrowed diagram and you should be able to find others. I like this one. It's colourful.

At 1/3 clay, silt and sand you are in the space between the Y and the L of Clay loam.

For a 100 ft2 garden, one foot deep, there is 100 ft3 of minerals - 33.3 ft3 of sand, silt and clay.

If you move to 50% sand, you will have 25% silt and clay. This now Sandy clay loam. An increase of 17 ft3 of sand or 0.63 yd3 per 100 ft2.

If you move to 60% sand, you will have 20% silt and clay. This now right on the line between Sandy clay loam and Sandy loam. An increase of 27 ft3 of sand or 1.0 yd3 per 100 ft2.

I don't know what kind of sand is available but coarse sand may give the best results. Hope this helps.


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RE: sharp/coarse sand to amend clay

As far as what to ask for, tell the supplier you want coarse and sharp, not fine or rounded sand. They'll know what you mean. It's also referred to as builder's sand, I think, but talk with them until you're sure they know what you want.

One thing's for sure, whoever suggested granite has not been to Ohio...I think it's all limestone over there, same as Indiana, Illinois and most of Missouri. :-]


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RE: sharp/coarse sand to amend clay

Clay soils are defined by the size, and shape, of the soil particles, not by how little sand might be there. If one looks at the most desirous soil, loam, it is about 45 percent sand, 25 percent silt, 25 percent clay, and 5 percent organic matter. if you have no silt then you would need to add that to the sand so you would need about 70 percent sand to add to your clay to make enough difference to be worthwhile.
Far less organic matter will make more of a difference and for much less cost.

Here is a link that might be useful: Amending Clay soils


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RE: sharp/coarse sand to amend clay

I tend to agree that organic matter will give you more bang for your buck. OTOH it has to be added constantly to clay (at least in my experience) to keep it from returning to its old ways, whereas changing the particle size distribution of the mineral fraction is more permanent. We add compost every year anyway for fertility too, and sand will not remove that need, just sayin'.

I prefer silty sand from the river bottom, which I can get when it floods. Nice stuff.


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RE: sharp/coarse sand to amend clay

For my soil, it might be more work and more expensive to add a soil compenent, but then I would have a problem solved long term. I also add organics every year in large amounts. But the bottom line is that my soil is still loamy fine sand and does not hold water well. Although organics/compost has improved my soil, it has not solved the long term problem for me. So I think if you are willing to do the work, and have an affordable source of sand, then go ahead and add it. In my garden which is 20' x 16' (320ft2) that would only take a couple of truck loads at most.


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RE: sharp/coarse sand to amend clay

  • Posted by RpR_ 3-4 (My Page) on
    Fri, Dec 28, 12 at 14:54

I do not know the price but crushed granite is available in Ohio.

If one wants crushed granite sand, always, ask for just that to eliminate any possibility of getting washed river sand.


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RE: sharp/coarse sand to amend clay

Organic matter in soil is what feeds the Soil Food Web and that is why it "disappears" fairly quickly and needs to be repaced regularly, just as Ma Nature does in the wild fields and forests. The Soil Food Web is not going to be able to live on sand, crushed shale, crushed granite, or any other mineral component one might add to your soil, they need that organic matter.
Perhaps spending some time with the linked Soil Biology Primer would be of help.

Here is a link that might be useful: Soil Biology Primer


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RE: sharp/coarse sand to amend clay

Can we just agree that our soils do need regular additions of organic matter....AND that many soils could be improved with some mineral additions that improve texture and fertility?

Yes . No


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RE: sharp/coarse sand to amend clay

Most all soils need regular additions of organic matter, swamps would be an exception. Whether any soil needs a mineral component depends on a number of factors. Texas A & M did amend soils with expanded shale and found that drainage kind of improved, when enough expanded shale was added and it took a lot, but that soil still needed additions of organic matter to support the Soil Food Web.
If the Agricultural schools of 50 states tell us that to make enough difference in clay soil drainage sand in the amount of 45 to 70 percent (Cornell) should that not be a clue that we should listen to what they are saying?


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RE: sharp/coarse sand to amend clay

I tried to buy it in the USA on ebay but they only had it in the uk, now they don't have it anywhere. There is a diease people get from breathing it. I did post when I was looking for it, but gave up. What they do have now on ebay looks fake to me.


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RE: sharp/coarse sand to amend clay

Everything you read will tell you it doesn't work but it absolutely does - you just have to add enough sand. My dad grew on orange clay backfill in PA. Make a raised bed and add the course sand on top. He always added course builders sand at 3 to 4 inches - plus and tilled it in to about 6" with a mantis tiller - and of course added 3 to 4" compost to the top every year. His beds were beautiful!

The raised beds get you above the clay which is a bonus as well.


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RE: sharp/coarse sand to amend clay

Clay is a mineral, silt is a mineral, sand is a mineral so if your soil is al mineral it may not be able to hold nutrients and moisture, both of which plants need to grow strong and healthy.
Organic matter, in soils, holds both nutrients and moisture and provides something for the Soil Food Web to munch on while the work to provide the nutrients the plants need. A lack of organic matter in soil creates all kinds of problems.


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RE: sharp/coarse sand to amend clay

Kimmsr, this is essentially a composting forum, and EVERYONE here recognizes, nay, advocates the use of copious amounts of compost. I don't think anyone here is suggesting sand or silt can take the place of compost for amending clay. So you can stop beating us with that stick.

It's not an either-or proposition, as illustrated beautifully by Albion's post. This is basically what I've done, although with less sand. I've added tons of organic matter to my clay over the years, and occasionally a bag of sand I come across or a wheelbarrow of river silt. I don't have concrete, I have raised beds with great soil. Either the high organic matter mitigates the 'concrete' effect, or I never added enough pure sand to get into the concrete zone, or I also added enough silt (or it was there in the silty clay to begin with), that I now have loam and not sandy clay.

I never went out to buy sand for the specific purpose of amending the clay, and I wouldn't necessarily advocate that, but there are some success stories right here. I would say that if you add enough compost to eventually fluff the beds into raised beds, that mitigates many of the problems with clay, so you don't really need massive amounts of sand.


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