# How long for pH to drop?



## BXMurphy (Aug 5, 2017)

How long does naturally acidic soil take to drop?

My UMass test came back with a neutral 7.0 pH. Around here, soils naturally tend to the acidic side and lime is typically an annual exercise. I very rarely lime as I've tended to neglect my lawn. I did a bag (40 pounds?) of dolomite on 2,500 SF around May. Last bag was 2-3 years prior. And then I discovered TLF...

I would like a soil at 6.5-6.8 in the spring. Should I apply gypsum or wait for a natural drop?

Modified Morgan extractable:

Potassium is low at 71 ppm

Ca:Mg seems crazy.
Calcium at 1336 ppm
Magnesium at 276 ppm

Shouldn't that be almost the other way around?

Base saturations:
Ca: 73%
Mg: 25%
K: 2%

CEC: 9.1

My thoughts are to throw some fast-acting gypsum and sulfate of potash at it. Light doses. See what happens.

I don't think the pH is the end of the world but the Ca:Mg looks like it could be a problem.

1. What affect will potassium have on this whole balance?
2. Will pH correct itself in a year or two or should I address it now for best results?
3. Do you think one bag of dolomite earlier in the year had that much of an effect?


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## social port (Jun 19, 2017)

BXMurphy said:


> How long does naturally acidic soil take to drop?
> 
> My UMass test came back with a neutral 7.0 pH. Around here, soils naturally tend to the acidic side and lime is typically an annual exercise. I very rarely lime as I've tended to neglect my lawn. I did a bag (40 pounds?) of dolomite on 2,500 SF around May. Last bag was 2-3 years prior. And then I discovered TLF...
> 
> ...


I don't have anything terribly substantial to say, but I'll toss some things out there. I looked into lowering ph several months ago and came away pretty discouraged. From what I remember, it is much easier to raise ph than to lower it. If you are really intent on lowering it, hopefully someone will come along with information that is more promising for your cause.

But on that note, why lower it at all? If you are rocking a cool season lawn, you're in a safe zone at 7, right? I believe that 7.2 or so is the upper limit of the _ideal_ range.

Finally, you might look into humic acid. From your reading, you might be convinced that it can give you some reduction in ph. How long that will take...not sure.


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## GrassDaddy (Mar 21, 2017)

You can add compost yearly to help lower it. Unfortunately it is a longer term project.


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## Ridgerunner (May 16, 2017)

> How long does naturally acidic soil take to drop?


Soils with a pH of neutral or below tend to become more acidic with the natural decay of OM and the application of N fertilizers.



> I would like a soil at 6.5-6.8 in the spring. Should I apply gypsum or wait for a natural drop?


Gypsum has little to no effect on soil pH.
Current pH is fine and it will likely slowly drop over time.
http://www.thelawnforum.com/viewtopic.php?f=22&t=250



> Calcium at 1336 ppm
> Magnesium at 276 ppm
> 
> Shouldn't that be almost the other way around?


Nope. "Ideal" Ca;Mg ratios are between 5:1 to 10:1, but detrimental effects haven't been reported for ratios as low as 3:1.



> 1. What affect will potassium have on this whole balance?


Not much, a little shuffling. Nothing detrimental as long as applied at reasonable rates and it is somewhat low and should be raised for turf availability. Why aren't you using the UMass recommendations that came with the test?



> 2. Will pH correct itself in a year or two or should I address it now for best results?


See supra.



> 3. Do you think one bag of dolomite earlier in the year had that much of an effect?


It didn't help. Lime takes about 1-2 years to affect the soil to the 4-6" depth. With a CEC of 9, it's more likely that liming in previous years created most of the current pH level, but it would depend on the quality of sampling and the status of the May lime application. Leave well enough alone.


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## LawnNerd (Sep 2, 2017)

BXMurphy said:


> Ca:Mg seems crazy.
> Calcium at 1336 ppm
> Magnesium at 276 ppm
> 
> Shouldn't that be almost the other way around?


No, that's a great ratio. If my maths correct (and it probably isn't) that's a great ratio at 5:1 cal:mag. Ideal is a 7:1 cal:mag ratio. I have the opposite problem. I have way too much mag and it can lead to tight (read compacted) soils. I also have a low ph (5) problem. I can only use straight cal lime (and of course solu-cal is adding in some dolimitic lime to fluff their bags) to help raise both my ph and cal levels.

Honestly, I wouldnt worry about it with that ratio and ph for a few years.


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## BXMurphy (Aug 5, 2017)

Ridgerunner said:


> > Why aren't you using the UMass recommendations that came with the test?
> > ...
> > Leave well enough alone.
> 
> ...


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## BXMurphy (Aug 5, 2017)

LawnNerd said:


> No, that's a great ratio. If my maths correct (and it probably isn't) that's a great ratio at 5:1 cal:mag.
> ...
> Honestly, I wouldnt worry about it with that ratio and ph for a few years.


Yes, you are right. After brushing up on high school math, I come in at 4.48:1.

Leave it alone... put down some SOP in smaller doses every month and a half or so... first dose like yesterday or wait until next year... and be happy to have met such nice folks around here.

Thank you.


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## Ridgerunner (May 16, 2017)

> Thank you for the link to the availability chart. I'm doing just fine...


Mightyquinn deserves the thanks.
Otherwise you're welcome.


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## LawnNerd (Sep 2, 2017)

Sorry, I should clarify. Buy leaving it alone I mean to leave the ph & cal:mag ratio alone, you're good there. Keep up with other macro and micro nutrients per your soil test.


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## BXMurphy (Aug 5, 2017)

LawnNerd said:


> Sorry, I should clarify. Buy leaving it alone I mean to leave the ph & cal:mag ratio alone, you're good there. Keep up with other macro and micro nutrients per your soil test.


Oh, yes... Thank you for the extra care.

It's so liberating to get away from the big-box 4-Step programs. Now that I know how to calculate nutrients per square foot and what those mysterious numbers on the bags of stuff mean... and do...

Man... what a waste of time, effort, and money I've been going through before finding TLF.

Such a pity... More's the pity when you try to explain it and you see eyes glaze over.

I have a tree-hugger in the neighborhood who likes to stop and chat. When I explained about recycled sewer sludge (Milorganite), I thought for sure that she would like that. Nope. "Ewww... You don't want to put THAT on your lawn! I use THIS (chemical)."


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## LawnNerd (Sep 2, 2017)

When I bought my house I just randomly decided that I needed to fert the yard. I went to my local big box and saw the 4 step and thought... This is too easy, something isn't right about this. Kinda like somethingin the air. In hindsight, it was probably the Milo I didnt buy. Instead I bought 10-10-10 and just winged it. No measure, no weighing... Yea it was a mess 2 weeks later. Lol.

I was surprised the hippie wasnt on board. That's only thing my wife's hippie friend approves of me doing. Lol


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## BXMurphy (Aug 5, 2017)

LawnNerd said:


> I was surprised the hippie wasnt on board. That's only thing my wife's hippie friend approves of me doing. Lol


I'm getting good at smiling and nodding and... walking away.

I was at a local feed and grain. The Nice Man just advised a customer on "winterizer." When he left, I explained that I would be putting down urea two weeks after top growth ceases and how I hope to time it right so I can feed the roots.

"Oh, that's too harsh, it's going to burn..."

Smile and nod...


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## 2xjtn (Nov 29, 2017)

Yes, aim for pH 6.5 to 6.8 for optimum nutrient availability. If you are already at the high end of Ca base saturation (i.e. >65-75%), then look to elemental Sulfur. Available at ag/coop centers. Golf courses here are starting to use a form of slow-release S. I use a product called Steric S. And you are also on the right track with humic acid - temporarily increase the cation exchange. Also, anything to improve the soil's biology, such as compost topdressing or liquid biology amendments will help break down nutrients. Think of this whole process as stepping on the gas pedal for a period of time. 
Cheers


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## HoosierLawnGnome (Sep 28, 2017)

I would say if you're trying to lower your pH with surface-applied gypsum, lime, and Sulfate of Potash, you will likely never see a drop in pH - and will probably see an increase.

Surface applied sulfur can be effective at lowering pH, but it requires long periods of warm temperatures, which doesn't exist in MA that I know of.

Besides, having an optimal pH isn't necessary to have an epic lawn. 7.0 isn't way out of the ordinary. pH is an over-rated metric to gauge soil health for turf.


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## bernstem (Jan 16, 2018)

7.0 is more than adequate for a stellar lawn. I wouldn't bother trying to reduce the pH - especially since your efforts are unlikely to be effective. In general, the lawn pH should gradually move lower as you are no longer applying lime and many common lawn practices (e.g. - many chemical fertilizers are acidic) will also gradually lower pH. I wouldn't bother trying to adjust Ca:Mg ratios. Your ratio is fine and both are more than adequate in absolute levels.

I do think you can likely benefit from pushing the potassium levels higher. Sulfate of potash is a good choice, but isn't likely to change the pH much. The sulfate in the SOP is not the same as elemental sulfur.

I don't see any iron level in your post. If it is low, one thing you might consider is foliar iron or chelated iron if you see suggestions of iron deficiency as iron becomes less available to higher pH.


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## Ridgerunner (May 16, 2017)

I disagree that pH is an over-rated metric to gauge soil health for turf or any other plant. It is probably the singular most useful tool for identifying possible issues. However, I do agree with everyone that an ideal pH of 6.5-6.8 is not necessary, leave alone critical. pH between 5.5 and 7.5 have not been found to result in poor performing turf. Of course, beauty is in the eye of the beholder.


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