# Temporary effects of lowered pH from elemental sulfur



## turfnsurf (Apr 29, 2020)

I am part of a distribution list with local master gardeners in my area. Because of my high pH, I was soliciting advice on where to find a local store that sells elemental sulfur. Someone made me aware of a publication issued by the University of Wisconsin Soil Lab which addresses lowering your pH.

Is applying elemental sulfur even worth it for me? I was just about to buy some, but I wanted to get an idea of what people thought. Please note the bolded sections.



> Many soils in Wisconsin especially in south-eastern Wisconsin are alkaline (high pH), and may contain free calcium carbonates.These carbonates are a source for alkalinity. Soils in Milwaukee, Waukesha, Kenosha and other eastern Wisconsin counties are a special case because they are marl-based. Marl is a finely divided calcareous material deposited when the area was an old lake bed. Having this marl-based soil means very finely sized highly reactive free calcium carbonate is present and soil pH can reach very high levels, (7.5 or greater). These alkaline soils having free calcium carbonate will require high levels of management to grow acid requiring crops successfully. *Adding a sulfur amendment to these soils that contain free calcium carbonate will probably not result in a significant pH decrease because all carbonate must dissolve before soil pH will change.* The amount of carbonate, its particle size and origin all affect the ability of a sulfur amendment to change pH. *Some soils having high carbonate content, especially if marl-based, will show little pH change even after large sulfur additions. If you have soil pH of 7.5 or greater, consider growing crops that do not require low pH. You will probably not be able to achieve or maintain and acid soil pH in these areas with reasonable applications of a sulfur amendment. *For most soils in the rest of Wisconsin that have a pH less than 7.5, you should be able to add elemental sulfur or aluminum sulfate in sufficient quantities to lower soil pH to the desired level. The change in pH will take 2 to 3 months, so if you should decide to plant crops requiring low pH it might be best to add sulfur this year and do your planting in the following year. Roots of these acid sensitive plants will not extend far beyond the acidified soil zone, so make sure the hole you prepare is adequate for expected root growth. The amount of elemental sulfur needed depends on the initial soil pH and the organic matter content of the soil. Have your soil tested by the UW Soil and Plant Analysis Lab, Madison or the UW Soil and Forage Analysis Lab, Marshfield to know the soil pH, organic matter content and other fertility levels are in your soil.Contact the Lab (608-262-4364 Madison or 715-387-2523 Marshfield) or your local county extension agent for sampling instructions. Sulfur is a soil amendment which can be used to lower soil pH. It takes about 32 lbs of finely ground elemental sulfur to reverse the soil pH change obtained with 100 lbs of lime. It is not desirable to use over 20 lbsof sulfur per 1000 sq. ft. at any one time. If more is required, use split applications of 20 lbs and apply in succeeding years. Check the soil pH before making a second application in order to see how much change has taken place.In order to lower the pH of the soil, sulfur must be oxidized by bacteria to sulfate. Sometimes the soil will contain very small numbers of this special kind of bacteria. Under these conditions, it will take longer for the bacteria to oxidize the sulfur, perhaps 6 months or more.


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## ken-n-nancy (Jul 25, 2017)

How high is your high pH? Is it above 8.5?

Generally, the approach for lawns in soils with high pH is to live with the high pH, but modify cultural practices to enable the grass to thrive despite the high pH and also ensure maintenance practices don't push the pH higher.

From what I've read (we don't have an alkaline soil in our own lawn), there are some standard "high pH lawn" practices:

Provide supplemental iron in a chelated form (such as in a fertilizer like Milorganite) or via regular spray of Ferrous Ammonium Sulfate (FAS) to provide iron directly to the grass.
Use Ammonium Sulfate (21-0-0) as the primary nitrogen source, which will nudge the pH lower over time (it is an acidifying fertilizer)
Continue introducing significant organic material (OM), which will help acidify the soil as soil microbes decompose the material.


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## ken-n-nancy (Jul 25, 2017)

ken-n-nancy said:


> How high is your high pH? Is it above 8.5?
> 
> Generally, the approach for lawns in soils with high pH is to live with the high pH, but modify cultural practices to enable the grass to thrive despite the high pH and also ensure maintenance practices don't push the pH higher.
> 
> ...


I just searched a little and found your soil test thread. Your pH is listed as 7.7, which is higher than optimal, but not so high as to mean you can't have an awesome lawn. Personally, I think stressing about your pH being 7.7 and trying to use elemental sulfur to lower it is likely to do much more harm than good.

Seems like you're already getting good advice in that thread from g-man. He said that his pH is 8; he has a very nice lawn, and he isn't stressing about his high pH.

For nitrogen fertilization, I'd suggest either using Milorganite, which will supply iron in a form that can get to the plant in your high pH soil, and should be a lot cheaper for you (in Milwaukee, WI) than for anybody else in the country, or for a fall quick-release fertilizer, using Ammonium Sulfate (21-0-0).

For supplemental iron (which will be needed due to the high pH), use either Milorganite or apply FAS, as mentioned above.

For potassium, use Sulfate of Potash (0-0-50), which is slightly more expensive than Muriate of Potash, but you should be able to get SOP from agricultural (farm) suppliers in Wisconsin.


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## ABC123 (Jul 14, 2017)

It's also hard to drop the ph if the irrigation water is also a higher ph.


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## turfnsurf (Apr 29, 2020)

ABC123 said:


> It's also hard to drop the ph if the irrigation water is also a higher ph.


What is the method for determining the pH of my irrigation water? And is there a workaround if there are pH issues with the water?


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## ABC123 (Jul 14, 2017)

turfnsurf said:


> ABC123 said:
> 
> 
> > It's also hard to drop the ph if the irrigation water is also a higher ph.
> ...


Pool strips or a calibrated ph pen. Something like a acid injection but It's not really worth it as they don't really make a product or system for it.

I just do the sulfur apps and call it good enough. Maybe it will help eventually.


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## turfnsurf (Apr 29, 2020)

ken-n-nancy said:


> For nitrogen fertilization, I'd suggest either using Milorganite, which will supply iron in a form that can get to the plant in your high pH soil, and should be a lot cheaper for you (in Milwaukee, WI) than for anybody else in the country, or for a fall quick-release fertilizer, using Ammonium Sulfate (21-0-0).


By quick-release fertilizer, do you mean liquid?


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## ken-n-nancy (Jul 25, 2017)

turfnsurf said:


> ken-n-nancy said:
> 
> 
> > For nitrogen fertilization, I'd suggest either using Milorganite, which will supply iron in a form that can get to the plant in your high pH soil, and should be a lot cheaper for you (in Milwaukee, WI) than for anybody else in the country, or for a fall quick-release fertilizer, using Ammonium Sulfate (21-0-0).
> ...


Being a quick-release fertilizer (also known as fast release) is separate from liquid vs. solid (granular), although liquid fertilizers are practically always quick-release.

Basically, quick-release nitrogen fertilizers are immediately available to plants. This is because they are soluble in water. Fertilizer labels sometimes call this Water-Soluble Nitrogen (WSN). These are contrasted with slow-release nitrogen fertilizers (also known as controlled release or Water Insoluble Nitrogen (WIN)) which have the nitrogen in a form that isn't immediately available to the plants and needs either time, or temperature, or moisture, or microbial activity, or some combination of all of these, to make the nitrogen available to the plants.

Both types have a place in lawn care, depending upon many factors such as the season, the grass type, the cost, the willingness to make frequent applications, the level of precision, etc.

In particular, late fall fertilization is generally limited to quick-release fertilizer types, such as urea (46-0-0) or ammonium sulfate (21-0-0) since there is limited time remaining before winter and the cooler temperatures generally make most "slow release" fertilizer types even slower than they would be in the summer.

Of these two, you'd be better off using ammonium sulfate (21-0-0) as AS has the side effect of lowering pH a little. Over many applications for many years, using AS as a fertilizer will gradually help move your pH in the right direction.

Some sources of additional information:

Turfgrass Fertilization Guide from PennState Extension
Choosing Fertilizers for Home Lawns from U. of Illinois Extension
Nitrogen Fertilizer Sources from Cornell


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