# How to improve clay soil for a lawn



## werc

I currently have an existing lawn with what I believe is clay soil. The soil is rock hard, and the water rolls off the lawn. I plan on tilling the lawn in, then adding something to improve the quality. Should that something be topsoil, mulch or ???. Also, how much of it should I need, such as 3", 6" or ???. I am a relatively newbie at this, but am just tired of having a brown yard no matter how much I fertilize or water. Any ideas are appreciated!


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## slakker

Besides water rolling off, have you dug into the soil to confirm? Other reasons that water roll off is thatch build up on the lawn. So aeration and de-thatching can fix that.


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## SecretSquirrel

werc said:


> I plan on tilling the lawn in, then adding something to improve the quality. Should that something be topsoil, mulch or ???. Also, how much of it should I need, such as 3", 6" or ???.


The best thing you can mix into clay soil is compost and processed manure. You could use non-processed manure but make sure it isn't fresh because it'll be stinky and contain high amounts of ammonia. You will hear differing opinions on mixing in sand and/or gypsum... some will swear by it and others will call it a myth. Although the sand will help to keep the clay broken up, it doesn't do anything as far as soil nutrition is concerned. I've used neither. You could also add some sphagnum peatmoss but I find that as a pricy option. For a new lawn I'd start with a good three to four inches of amendments and work it in as deep as possible. It is suggested that you go as deep as 18" - 24" but that often is not practical. Do the best you can with what you got. After working in your amendments step back and evaluate it to see that you have a good balance and add more if required, but don't over do it

This past spring I broke ground on some additional garden space. I used the scarifiers (tines) on a box scrape on my compact utility tractor to break the ground... then followed up with the tiller. It was hard clay and I thought I was riding a bull trying to get the tiller through there. I eventually got the clay busted up then worked in a sufficient quantity of good rich compost (looked like loam). I've had no problem all summer long being able to cultivate that new soil mix and I've got Roma tomatoes coming out the wazoo. :biggrin:


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## werc

slakker said:


> Besides water rolling off, have you dug into the soil to confirm? Other reasons that water roll off is thatch build up on the lawn. So aeration and de-thatching can fix that.


Very good questions. I am not 100% sure it is clay, but we have thatched and aerated for the last 3 years, and it did not seem to help much. We also have several flowerbeds that the water just rolls off. It is actually pretty wierd, because we can water the flowers, and when all the water rolls off, the dirt does not even look like it had any water on it. It is the oddest stuff I have ever seen.


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## werc

SecretSquirrel said:


> The best thing you can mix into clay soil is compost and processed manure. You could use non-processed manure but make sure it isn't fresh because it'll be stinky and contain high amounts of ammonia. You will hear differing opinions on mixing in sand and/or gypsum... some will swear by it and others will call it a myth. Although the sand will help to keep the clay broken up, it doesn't do anything as far as soil nutrition is concerned. I've used neither. You could also add some sphagnum peatmoss but I find that as a pricy option. For a new lawn I'd start with a good three to four inches of amendments and work it in as deep as possible. It is suggested that you go as deep as 18" - 24" but that often is not practical. Do the best you can with what you got. After working in your amendments step back and evaluate it to see that you have a good balance and add more if required, but don't over do it
> 
> This past spring I broke ground on some additional garden space. I used the scarifiers (tines) on a box scrape on my compact utility tractor to break the ground... then followed up with the tiller. It was hard clay and I thought I was riding a bull trying to get the tiller through there. I eventually got the clay busted up then worked in a sufficient quantity of good rich compost (looked like loam). I've had no problem all summer long being able to cultivate that new soil mix and I've got Roma tomatoes coming out the wazoo. :biggrin:


Thanks for some great tips, and the detailed post. We have just always talked about tilling in topsoil, primarily because we just did not know what else to use. Thanks!


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## AZJD

werc,

Wet some soil and roll it into a ball. If it _stays_ in a ball, it's clay. If it falls apart, you're okay.

Like others have said, you probably need to amend the soil by adding organic material, such as manure, mulch, or peat moss. I would also add sand to improve the drainage. Water and fertilizer don't help much if they can't get to the roots. The deeper you can go; the better. Good luck.


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## SecretSquirrel

AZJD said:


> Like others have said, you probably need to amend the soil by adding organic material, such as manure, mulch, or peat moss.


AZJD, when you said "mulch", did you actually mean to say "compost". I wanted to clarify that because mulch is not a good soil amendment as it has not "composted" yet, but as it goes through that process, it uses high amounts of nitrogen which depletes the soil of that much needed element.


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## darsunt

Note that heavy clay soil can be very resistant to a tiller. I recall one contractor hiring day labor to turn over the entire area with spades, before running a tiller over it.

My area is southern, semi desert, we have very heavy alkaline clay soils.


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## werc

thanks again everyone. I am finishing up my retaining wall project, and getting ready to tackle the yard!


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## reny

*Clay soil & Grading*

 Thanks everyone for your advice on amending clay soil. I have the same NJ red clay soil. Very rocky too. I'm planning on working on it this summer. I would like to try some gypsu or calcium sulfate. Does anyone know a good cheap source?

Re: grading the front yard. The 'lawn' is vary uneven. I just had a handicapped ramp built. Do I have to start grading from under the porch & ramp? I think the center of the 'lawn' is higher than under the porch.


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## Jamboy

All of the advice given is good but if you are talking about spending the time and money to establish a lawn that will last and know what you need to do to keep it looking its best, take advice from a real professional. I don't mean me but a book written by one of the best in the business. It is "Lawn Geek" written by John "Trey" Rogers who is the head of the Turfgrass program from Michigan State. It is written for homeowners and not for scientists or experts. He also has a Q and A area on gardenweb.com as well as an interactive tool on Briggs and Stratton's website under lawn doctor. The specific address is yardsmarts.com/yard_doctor/.

He has overseen the fields at the last two summer Olympics and almost all USGA events. Don't think he is going to give advice that is way more than you could afford or even want. He is a regular guy who loves grass and wants people to enjoy their yard without getting frustrated or worse doing it wrong and having to spend more money and time to correct what was done.

You will find a lot of people that will give advice. Some of them will be knowledgable but none will come close to Trey's understanding and his easy way of explaining what is needed. His whole life is devoted to grass. It doesn't matter if it is the Olympic Stadium field or your lawn, he will do his best to get you the results you want. He gives his advice to anyone online and his book isn't expensive for that reason.

Give one or all of his sources for information. You won't be disappointed.

Good luck,

Jamboy


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## reny

*Thanks*

Thanks for the book tip Jamboy. Reading will probably wait until summer. I am hoping for improvement Next Year.


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## downunder

Always give your location when asking for landscaping advice!



> I currently have an existing lawn with what I believe is clay soil.


With any problem, you need to diagnose it first. There has been good advice given, but it may or may not be what you need. Take a soil sample to you local extension office and find out exactly what you have to deal with.

Tell us where you are, and what you have, and we can help you more successfully.


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## Kristof

Hi guys
I bought a house with 1 acre of yard. Each time when there is a rain after all the yard is wet for next 2-3 days. I know that my soil is a clay. How I can treat the clay soil? I need to fix the whole 1 acre. Is there are any mixture that I can spray during watering my lawn?


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## Jamboy

There is no easy solution to amending your soil, especially soil that is almost all clay. The previous poster noted you needed to state where you were before anything else. This is somewhat true but the most important thing is determining the makeup of your soil wherever you are. There are plenty of resources on the web that describe how to take a soil sample(s) and where to take it to have it analyzed. This report will give you the content (clay, sand, silt), mineral levels, amount of organic material and pH. It will usually recommend what your soil needs to be considered loamy. If you have seriously compacted clay with almost no topsoil, you aren't going to have many choices. A healthy lawn, one with strong grass plants, needs a layer of soil that allows for root growth of 4 to 6 inches. I can tell you from multiple experiences, there is no easy way to achieve this. _*If *_after you get your sample back, and it is heavy clay and you really want to grow a really healthy lawn, be prepared to start from scratch. Remove the existing sod (use anything healthy elsewhere), remove 4"+ of the clay, loosen up the next two inches of soil (make sure to remove every rock, root, or any debris you find), mix in the recommended amendment, cover with a high organic topsoil in at least two stages. You need to lightly compact the soil at some point to determine low/high points and regrade those spots. After you get a good smooth grade, add the remaining topsoil and repeat the light compaction to ensure the grade is still intact. How high the level of the topsoil depends on whether you are going to sod or seed or plug. Sod has a layer of topsoil that will add an inch or more to what you have so consider that beforehand. Whether seeding or sodding, you will want to soak the topsoil to a depth of about 4" trying not to have the soil erode. After the top is dry enough to work on, scarify it and put down the seed/straw or sod. Put down a good slow release starter fertilizer and keep the soil as moist as possible to ensure you maintain that good depth of moisture. If you sodded, use a 1/4 filled hand roller to make sure the sod and soil really "bond". Another secret I learned from Dr. Rogers is to set aside a good amount of topsoil for after the sod is laid. The edges of sod are prone to drying out so use this topsoil as a way to decrease this possibility. Lightly sprinkle the remaining topsoil along edges and along seams. After the repeated watering you will be doing, this light coating will act like "lawn caulk" and will disappear leaving you with less noticeable seams and burn marks.

I hope this helps. People will try to aerate there lawns removing the plugs a couple of times per year and topcoating with topsoil. That may be an option but it takes years to achieve success, if you can. If someone says they can grow a healthy lawn in dense clay, don't even listen. If there was a way to do it, there are a lot of very educated minds and dirty hands that would pay a lot of money for that secret.

Jamboy


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