# Tips for clay soil



## sam36 (Apr 14, 2020)

I was going to go to my local site one and pick up 200lbs of gypsum to put down on 10k sqft of newly sprouted bermuda since it seems to be struggling to grow and putting out any more fertilizer would just burn it and slow it more. But I happened to look at my soil test from last year (didn't get one this year yet) and noticed that my sodium levels were pretty low:



I was thinking that they were probably high, hence the gypsum. Should I still grab the gypsum (and anything else?) since it seems to be the thing to do with clay? And from what I read, 20lbs per 1k sqft are typical rates, seems high though but I can do it.


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## occamsrzr (Apr 27, 2020)

sam36 said:


> I was thinking that they were probably high, hence the gypsum. Should I still grab the gypsum (and anything else?) since it seems to be the thing to do with clay? And from what I read, 20lbs per 1k sqft are typical rates, seems high though but I can do it.


I would not apply any gypsum. There is the idea that gypsum improves soil tilth in clay. I am not so sure there's much evidence to back this claim. Looking at your pH and Calcium levels, I think applying more gypsum isn't going to help your situation. If I were spending money, addressing your pH would be a better investment in time and money.

Gypsum is good in acidic to neutral soils where you are trying to correct Ca:Mg ratios. You have maybe one of the highest Cal ppm I've seen. Adding more Calcium to your soil won't deliver drastic results.


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## g-man (Jun 15, 2017)

It is still too cold for bermuda to be actively growing. Give it a couple of weeks.

This soil needs phosphorus and sulfur. I doubt elemental sulfur will change the pH due to all the limestone, but it can provide some of the plant sulfur you need.

Check the soil remediation guide for more details about what products and rates to use.


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## sam36 (Apr 14, 2020)

For the last year, I've just been dumping ammonium sulfate and diammonium phosphate. Not sure what else I could do. I did dump out a bag of humic DG the other day, but expensive... Would going to site one to get a few bags of Mirimichi Green CarbonizPN be worth it or just keep up with the DAP and AMS? I also noticed my local "soil and rock" store is selling fertilizer made from a local "waste water plant", pretty cheap too. That might be an option.


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## g-man (Jun 15, 2017)

How many pounds of DAP per Ksqft for the year?


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## sam36 (Apr 14, 2020)

g-man said:


> How many pounds of DAP per Ksqft for the year?


So far for this year? Let me think. I've been mixing half and half AMS and DAP. Did 3 apps but they weren't exactly 50/50 mixed. So somewhere from 4.7 - 5.3 lbs total for the year of DAP and 10.5 to 12 lbs total fertilizer (AMS included).

I've got one 50lbs bag of DAP left, but sounds like I need to wait a couple of weeks before applying anything again. On established grass last year, I seemed to get better results from doing an app of AMS at 5lbs, wait 10 days, then doing an app of DAP at 5lbs instead of trying to do two 50/50 apps. But kind of felt like full strength DAP would raise my PH and not lower it so dunno.


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