# Ammonium Sulfate - How Potent of an Effect on Ph?



## FlyersFn32 (Jul 4, 2018)

Starting to get antsy here in southeastern PA!

Just got my soil test back and I was very pleased with most of it. My iron levels are plenty high, but I've never seen the remarkable dark green color some of you have. My PH is 7.0. I'm hopeful that bringing it down some to the ballpark of 6.5 might allow the turf to access more of the iron that's already in the soil.

My plan is to mostly fertilize with ammonium sulfate this season in an attempt to bring that PH down a bit. My question is if I apply 3.5-4.5 lb of 21-0-0 ammonium sulfate (for between .75-1.00 lb of N), how much can I expect the Ph drop per app, or how many apps would you estimate I'll need until I get down to 6.5?

My other option or combined approach is elemental sulfur, but I believe ammonium sulfate is faster-acting, correct?

Thanks!


----------



## g-man (Jun 15, 2017)

Check the Soil Remediation Guide. The Purdue article gives you estimates of how many pound of X material = 1lb of elemental sulfur.



> If soil pH is above 7.0, then the best way to reduce it is with elemental sulfur at 5lb/ksqft per hot weather season (once a year in northern states vs twice in Houston, TX). Why? Elemental sulfur needs a microbial breakdown to convert it to sulfuric acid and release the hydrogen which is what reduces the soil pH (more info in this Ohio State article). Too much elemental sulfur without the microbial activity can lead to accumulation and too much being released at once (hurt your lawn). There are other ways to reduce soil pH and this Purdue article describes it and this Iowa State article.


----------



## Ridgerunner (May 16, 2017)

@g-man I wonder why the Purdue charts recommend 10X the amount of elemental sulfur as the Iowa charts (reprint of Clemson info) to get the same reduction in pH. Strange that it is a factor of 10 throughout the chart.


----------



## Pete1313 (May 3, 2017)

@Ridgerunner, the iowa chart is per 10 sq ft and the Purdue one is per 100 sq ft


----------



## Ridgerunner (May 16, 2017)

@Pete1313 Thanks Pete, I didn't catch that. Thought both were for 100


----------



## FlyersFn32 (Jul 4, 2018)

@g-man so because I have clay soil, I need 15/16 lb of elemental sulfur to bring my PH from 7.0 to 6.5.

1 lb of sulfur = 2.8 lb of ammonium sulfate. That would mean I would need to use at least 42 lbs of ammonium sulfate to get there. Obviously that will take several years.

Can I go with a two-pronged approach of using ammonium sulfate as fertilizer AND apply elemental sulfur? From what I've read, ammonium sulfate releases hydrogen into the soil which increases acidity, and sulfur gets converted to sulfuric acid. Do they ultimately act on the Ph via different means, or if I fertilize with AS while I also have elemental sulfur undergoing its biological change in the soil, will I kill my turf?


----------



## g-man (Jun 15, 2017)

They both bring Hydrogen into the soil, so both will have the same effect. By the way pH is logarithmic scale that inversely indicates the concentration of hydrogen ions. The AMS rate is very low, so it wont kill the turf to do both. The 5lb/ksqft does have some safety factor into it.

Another item to consider, your water. If you irrigate using a high pH water (aka hard water), then it could increase your pH.

Like I wrote in the guide, you can have a great lawn at high pH. Look at Pete1313's lawn and I think Connor's and Ryan Knorr. Just tweak your practices towards it and it will be fine.


----------



## Ohio Lawn (Mar 20, 2019)

g-man said:


> They both bring Hydrogen into the soil, so both will have the same effect. By the way pH is logarithmic scale that inversely indicates the concentration of hydrogen ions. The AMS rate is very low, so it wont kill the turf to do both. The 5lb/ksqft does have some safety factor into it.
> 
> Another item to consider, your water. If you irrigate using a high pH water (aka hard water), then it could increase your pH.
> 
> Like I wrote in the guide, you can have a great lawn at high pH. Look at Pete1313's lawn and I think Connor's and Ryan Knorr. Just tweak your practices towards it and it will be fine.


What other practices can be tweaked? Obviously using AS as the N source is one. Could you suggest a couple others?
Thanks.


----------



## bernstem (Jan 16, 2018)

At a pH of 7, you don't really need to change much. At most foliar Iron applications if you want darker color. I agree with Ammonium Sulfate fertilizer. I wouldn't bother using elemental sulfur personally, but it won't hurt. You may find it useful to search for nitrogen and ECC (effective calcium carbonate).

https://www.blinc.com/role-nitrogen-fertilizer-soil-ph


----------



## turfnsurf (Apr 29, 2020)

bernstem said:


> At a pH of 7, you don't really need to change much. At most foliar Iron applications if you want darker color. I agree with Ammonium Sulfate fertilizer. I wouldn't bother using elemental sulfur personally, but it won't hurt. You may find it useful to search for nitrogen and ECC (effective calcium carbonate).
> 
> https://www.blinc.com/role-nitrogen-fertilizer-soil-ph


@bernstem I have a ph of about 7.1 and I intended on using elemental sulfur to get my soil down to about 6.5

Why would you personally prefer using ammonium sulfate fertilizer over elemental sulfur for just a minor change?


----------



## Ohio Lawn (Mar 20, 2019)

turfnsurf said:


> bernstem said:
> 
> 
> > At a pH of 7, you don't really need to change much. At most foliar Iron applications if you want darker color. I agree with Ammonium Sulfate fertilizer. I wouldn't bother using elemental sulfur personally, but it won't hurt. You may find it useful to search for nitrogen and ECC (effective calcium carbonate).
> ...


I have the same question.


----------



## turfnsurf (Apr 29, 2020)

I had to edit my post...I tagged the wrong user...LOL @bernstem


----------



## bernstem (Jan 16, 2018)

@turfnsurf @Ohio Lawn A couple of reasons. A pH of 7.1 is really not that high and really won't negatively impact nutrients very much. In practice, it means that you would be chasing a pH number that likely does not have any demonstrable impact on your lawn. Secondly, depending on why the pH is 7.1, you may not be able to change it easily, even with sulfur. If your irrigation water, for example, has a pH of 8.5, that will work against you. If it can be changed, you don't need to reduce pH very much, so Urea and Ammonium Sulfate will both slowly acidify the soil. Of the two, Ammonium Sulfate is more acidifying, but both will push the pH down.

Bottom line, for me, though would be to look at the grass. If it is performing well and doing what you want, you don't need to chase a number. If it isn't performing the way you want, and you have fixed issues more likely to improve the turf, then start looking to move the pH more aggressively than just with Nitrogen sources. If you just want to play and see what happens, try the sulfur. It won't hurt. You can certainly use both Ammonium Sulfate and elemental Sulfur.


----------

