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How to improve all-clay Utah soil?

Posted by imspaulding zone 6 UT (My Page) on
Mon, Jul 11, 05 at 13:59

We have purchased a new home in DayBreak, in South Jordan Utah, and the soil is completely clay with a little sand. There is no topsoil at all; it was scraped off and removed from the entire subdivision. We are willing to bring in topsoil or other materials to amend the soil, but what should we use, and where do we get those things? Has anyone dealt successfully with this kind of soil situation?


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RE: How to improve all-clay Utah soil?

If you're willing to add enough sand, adding sand will make a permanent change to the soil structure and loosen it up. However, it is difficult to add enough sand, and if you add too little, you can make it worse.

Because of the possibility of making the soil worse, many people recommend adding lots of organic matter instead. If you don't add enough organic matter, it will still help, just not as much.

From a website on utah.gov:
"Mulch is available from the South Utah Valley Solid Waste District at 1400 South Industrial Parkway as well at most home and garden centers. Call 489-3027 for availability."

If you haven't planted the lawn yet, you can work it in. Otherwise, you can just spread it on top (no more than about 1/2 inch thick or it will cover the grass).

If you're anywhere near a Starbucks (a full Starbucks, not an airport one or a Barnes and Nobles one), they have a program called grounds for the garden and provide used coffee grounds free to anybody who wants them (and you don't need to buy anything). They usually have bags of grounds in a bucket near the door, but if not, you can ask. You can just toss them around the lawn, although I think some people have dried them and used a spreader.

Sam's club and Wal-Mart sell something called Revive. The version at Sam's is dry and is on composted poultry manure and can be spread with a fertilizer spreader. The stuff at Walmart is in a hose-end sprayer. It is supposed to help loosen the soil and also act as a chelating agent to help your plants absorb different minerals (Utah soil tends to be high pH, and plants often suffer from iron chlorosis, where the leaves turn yellow or yellow with green veins). I bought some and applied it, but I'm not sure how much it helped.


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RE: How to improve all-clay Utah soil?

We haven't planted the lawn yet. The backyard (about 2500 square feet) is just a hardpan crust right now. I guess we were thinking we would try to bring in about 3 truckloads (36 cubic yards) of topsoil, but I have been told that most of what is sold as "topsoil" in Utah is actually just subsoil fill (ie, more clay), so we are not sure we can even find real topsoil. Do you know of a source? Perhaps we are better off with mulch and a rototiller.

By the way, am I wrong about being in Zone 6? We are at the far western edge of South Jordan, up at the Oquirrh Mountains foothills. It is dry, but at a significantly higher elevation than the Valley floor - sort of similar to "the bench" on the Wasatch side, except it doesn't catch as much precipitation.

Anyway, any advice would be appreciated.


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RE: How to improve all-clay Utah soil?

I'm in Utah county and have had dump trucks of "garden top soil" delivered by a couple of different companies. While one was significantly better than the other, both were just heavy clay undersoil with a bit of peat and/or sawdust mixed in (the better one had a bit of manure too). One was silty clay that forms a crust which repels water better than anything else I've seen. The other makes pinch pots just like the stuff in my yard. The only advantage over my own "dirt" was that it was missing the "Orem potatos" (rocks). I needed fill to level my yard, but for my kitchen garden, I'm just sifting my own clay and mixing it 1 part compost to 2 parts clay. Plants in my own dirt are generally doing better than those in the imported stuff except where I ammended the imported stuff the same way I do the native stuff.
If you don't need fill, I'd just ammend the existing clay. If you bring in dirt, I'd suggesting inspecting what you're getting before you buy. Keep in mind freshly sifted clay looks pretty good. Bring along some water and see what happens when it gets wet. Better yet bring along a soil test kit. I wish I had.

Utah/Salt Lake valley ranges from 5b-6b (-15 to -5). Most of it is 6a, but the higher elevations away from the lakes are 5b, and the south end of Utah lake is listed as high as 7a. If you want to be safe, plant zone 5. If you plant zone 6 or 7, count on needing to replace the plants once every 5-10 years.


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RE: How to improve all-clay Utah soil?

I'm from Illinois, so I've got certain expectations of what topsoil should be. My idea of what topsoil should be is very similar to what my garden soil now looks like, after 9 years of composting. I always thought soil was black, but when I moved here, I learned that it is often yellow.

I bought a load of topsoil, and it turned out to be clay mixed with pea gravel and shredded wood. One thing to note is that with our conditions, manure isn't always a good choice as an amendment. Due to the need to irrigate, salinity is a problem, and manure tends to exacerbate this.

I would be inclined to bring in as much compost or even shredded trees as you can. If you can find a tree service, they might deliver shredded trees for free (it saves them paying to dump them).

You could probably even bring it in now and just spread it on top of the soil. A lot would break down before it's time to plant the grass, and what doesn't break down would work into the soil more easily after a few months of letting it decompose, letting the worms work the soil, etc.

Since you haven't planted the grass yet, you almost can't overdo the amount of compost, shredded trees, etc you bring in. Once you have a lawn in place, you shouldn't apply it more than about 1/2 inch deep (1 cu yd will cover 648 sq ft to 1/2 inch).

As far as the hardiness zones go, I've learned to err on the side of caution. The problem is that the hardiness zones are based on the lowest winter temperature. It got much colder in the winter in Illinois than I've ever seen here, but the last snow was usually in January or February, and the last frost was usually in March. We usually had our garden fully planted by the beginning of April. I've learned that the only reason to plant before mid May here is if you like planting repeatedly.


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RE: How to improve all-clay Utah soil?

My experience with Utah topsoil is similar to the ones related here. It's not very good stuff but at least it's free from rocks. But that's what you want when planting grass. I've got places where the rocks are just under the lawn and I'm slowly "raising" it by adding topsoil a half inch at a time. Much better to add it before the lawn goes in!


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RE: How to improve all-clay Utah soil?

Hello neighbor!!!

I live in Daybreak as well!!! Go figure! Anyhow, yes.. you are correct about being in Zone 6. We added compost to our soil and then added about 4" of topsoil on top. You CAN buy topsoil here in Utah. Make sure you asked for screened/clean topsoil and not fill dirt. It is common for the builders to scrape off the top layer of good soil and sell it. Then, lucky us... we get to buy it back.

If you want to learn more about gardening for Utah conditions, the HOA is putting on a gardener's seminar later this month. As always, you can feel free to e-mail me at anytime and we can chat. :-)

shycheerleader@yahoo.com


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RE: How to improve all-clay Utah soil?

I have lived with west jordan clay; my suggestions are:

Soak, wait 12 hours, till your soil to a depth of at least 8". The clay must be fine and crumbly.

Take a pickup with sheets of plywood for side extenders to Lynnleigh Farm at 10777 S State St, Sandy, UT. For $5 they will fill it with 1 year old weed free horse manure / sawdust compost.

Cover the area with compost 6-8" deep.

Till thoroughly, water normally, level high, use rolling leveler to compact, plant sod. It will shrink after planting. You have created 'topsoil' equal to or better than that normally delivered.

For the garden area, as above + till spring and fall and cover with fresh 2" aged compost as mulch; your shoes and knees will stay much cleaner.

By the end of the second year, you will have the best loamy clay soil & garden in the neighborhood, filled with all the necessary nutrients.

Clay loam makes superb garden soil; it holds water superbly. Dried pulverized clay is the ammendment used for mineral depleted soils.

This post was edited by Stormygale on Tue, May 6, 14 at 13:50


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RE: How to improve all-clay Utah soil?

>> Take a pickup with sheets of plywood for side extenders to
>> ... they will fill it with 1 year old weed free horse manure / sawdust compost.

Butting in as an interloper NOT from Utah but who has adobe soil, what Stormygale said is gold.


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