Question on using Elemental Sulfur to lower PH

So I do feel like a lower ph would be very beneficial for all of my fruit trees. My soil ph is more alkaline and the water used to irrigate is definitely very alkaline. I’ll do a formal soil testing soon but knowing what I know about soil around San Diego and the tap water and doing some ph test kits, I’m 100% positive that the ph is above 7. I have other plants as well that would benefit from a lower ph (lots of bamboo). Everything I’ve read indicates that elemental sulfur is the best choice for dramatically lowering ph a full point for a longer period, but they all recommend applying it before planting. Since that is not an option for me, would it still work by adding the sulfur to all of the soil areas around the trees and plantings?

Yes, it will work, but will take 6 months to a year to work. I add fresh sulfur to my blueberries all the time. I just work it into the surface as best possible. I used soil acidifier, but just bought some micronized sulfur to add this fall. For me during the winter pH rises on me. So this is my plan to counteract.

It won’t work if your soil has free carbonates, ie limestone. If those are present then it would generally takes piles of sulfur and the results won’t be uniform. You might end up with pH ranging from 3 to 7. If your soil lacks free carbonates then there is the chance you could make some progress without hurting anything.

Lowering pH isn’t helpful unless you are suffering iron chlorosis or some other nutrient issue associated with high pH.

You can have a soil test done for free carbonates.

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Think we’ve got a fair amount of limestone in our soils here in San Diego county. As well as granite. And, as fruitnut mentions, it really is a big waste of time. Your trees will acclimate. They might be a wee bit chloritic in the early spring when they’re young, but they will adjust. It’s an awful lot of work for very little return. The only thing you’ll not be able to plant in-ground will be blueberries. We can do blueberries, but they need to be in containers. Check DWN’s web site on how to do that. Their technique works very well.

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My soil is clay loam and iron and sulfur work well. You could acidify the water, and also use ammonium sulfate and chelated iron.

Fruitnut, why would it matter with trees and shrubs if the results were uneven? Plants could presumably extract iron from the more acidic parts of the soil. I know with experiments Carl Whitcomb made with pin oaks, he was able to relieve the trees of chlorosis by merely spreading sulfur on the surface. The improvement was fairly rapid even though measurable pH was not altered except on the very surface.

I was fooled for years by blueberries that were thriving in a pH of 6.5 or so. I thought the fact that plants were mulched was freeing iron with humic acids released as mulch decomposed. Turned out the upper 10 inches or so of soil was almost sweet but the soil below was about 5.5.

At any rate, spreading a reasonable amount of sulfur might be a worthy experiment if plants seemed deficient in iron.

That’s cool about the blueberry discovery, it makes them grow deep roots too, a win win situation! Yes I think it’s worth trying too. If you did it once or twice a year, the trees should load up on what they need. I listen to a Utah garden podcast and maples there that are not native suffer from iron chlorosis. They use chelated iron (it works very fast!). I would suggest trying that too, it has to be chelated to work quickly. In Utah it’s the limestone too that is the problem. The garden radio host said it works well. One application each spring. He does suggest using local maples instead, but if you have the trees already…
I’m spreading some Chelated iron around next week. i noticed some yellowing on my blackberries. I’m going to hit them, the raspberries, and the blueberries.

If you have a soil with buffers (free carbonates) you have to apply enough sulfur to “burn up” the carbonates before you can lower the pH. Clays are harder to change than sandy soils. I have not seen the extension service recommending to apply sulfur to lower pH in limestone soil areas but they do recommend using sulfur based fertilizers like ammonium sulfate. Mulch will also provide micro climates with reduced pH that help in very alkaline areas.

Womack nursery suggest using Halford rootstock for peaches in areas with high pH. I think it is considered high pH when it is 8.0 or above.


We do have calcium-infused sands and clays in most portions of the metropolitan areas. I don’t recall seeing any limestone on the soil maps. However, the geologic surveys taken prior to urbanization show that the native soils had a pH in the range of 5.8 to 6.2. But this all changed when we began irrigating with municipal and well water with pH ranges from 7 to 8.9.

A common lesson in the agriculture of arid and semi-arid lands is that the pH of the irrigation water will set the pH of the soil. This is why I fertigate. An alternate approach is to regularly supplement the soil. In the latter approach it is a learning curve to determine what quantities of acidifiers are needed to offset (a) alkaline minerals in your soil, and (b) non-acidic properties of your irrigation water (if any).


I just do things by hand. I water by hand, i adjust the pH by hand. I grow plants with extreme differences. Some require an alkaline environment, some acidic. Some require more water or less water. So I find automation having to be too complex. It’s easier for me to just do it by hand.
It takes longer, but the longer I stay in the garden the better. During harvest which starts any second, it is time consuming for sure.


I have three blueberry plants that have grown very little for the last three years and I was considering moving to another part of my yard. Then I started reading about how the soil ph if high would lower vigor. Along comes the idea to put the leftover sulfer water from my sprayer around my plants. To my surprise the three plants are growing well now. Has anyone else tried using the leftover sulfer water to lower the immediate area around the plants? What was your results? Will this damage my plants if I continue? As of now the plants are looking better than they ever have. I would like to hear your thoughts about this or other methods of lowering the ph in established plants.

Auburn, get a simple but reliable pH kit. You are fine if you don’t take it too far but you don’t want to do this simply with guess work. You can also take soil samples to your cooperative extension for an inexpensive pH test.

Those of you who have dealt with calcareous soils and irrigation water that have tried various tactics to deal with the issue obviously have a more legitimate perspective on what can be accomplished from sulfur than I do, by the way.

FN and Hoosier are more qualified to answer the question than I am, but I love a discussion.

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Thanks Alan

I bought sulfur that is very fine to add to water to use only on my blueberries. So yeah you can do it.

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It appears to have made quick changes that helped my blueberry plants. I will be testing the soil soon because I just don’t know how long and how many times to apply the sulfur. Right now the plants really seem to be benefiting from the application. Bill

I agree you need to test soil, I test mine monthly.

Sulfur doesn’t make quick changes to pH. It would takes months. What you are seeing is likely something else.

High pH causes chlorotic growth of blueberry more so than slow growth. If the plants have decent color but slow growth that’s more likely a lack of fertilizer or maybe water than pH. Usually what’s needed to spur growth is nitrogen.

I did fertilize the plants more this spring and we have had more rain than normal. Good points. Thanks, Bill

Bill, what fruitnut said. You’ll know your pH is too high with blueberries, as they grow poorly and take on a reddish/bronze chlorotic appearance. We do have some test commercial blueberries growing in our area in the ground, but with some serious in-line acidification in the irrigation systems. It has worked very well, but it takes some up front work to set up. Richard mentions his “fertigation” system, and this is what the commercial blueberry growers are using, along with adding I think muratic acid to acidify the water, along with fertilizer. Soil sulfur will work, but it takes several months to break down and affect the soil pH, and it needs to be carefully reapplied every couple of years. Here are a couple of good links about growing blueberries and adjusting soil pH from DWN:

And in containers:

Thank you