# PH Question - Clay soil



## SoilSecrets (Apr 12, 2019)

I was planning a fall lawn renovation until My soil test said the PH is highly acidic 4.5. The soil is mostly clay. I spread calcitic lime (cal turf pro) at 12lbs per 1000 sq. Ft. over the weekend.

Roughly how much time will it take to get to 5.5 then 6.5? I am trying to get an idea of how many lime applications I'll need to see some improvement. Would liquid humic help drive the lime into the soil more effectively?

Would it be a waste of time to plant cool season grass TTTF, KBG in the early fall 
with PH this low? Any other ideas would be welcome.


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## Ridgerunner (May 16, 2017)

Estimates vary from 1 year to 2+ years for a loam soil to the 4-6" depth. There are a number of variables. Too many. Low pH is the result of hydrogen build-up in the soil. Lime neutralizes it. High CEC soils at any pH <7 will hold more H+ than a low CEC soil at the same pH, so it will take more lime to change the pH. The quality and type of the lime product and how finely ground will also effect the speed as finely ground lime will react quicker and MgCO3 reacts much slower than CaCO3. Also, how well the soil drains will influence how quickly pH will change to depth. Then there's adequate irrigation...


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## LeeB (Jul 1, 2019)

Adding lime to clay works way better and faster if you can mix it into the soil with tillage. If you are going to renovate, that is the time to add lime for sure. However you need to calculate how much using your CEC number from your soil test. If you are tilling, you might add as much as 300 lbs lime per 1000 to correct severely acidic soil.

If you haven't, I would get an agriculture-style soil test that will give a liming recommendation.


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