Anywhere from a week to 6 months.

If you are using granulated, or prilled agricultural sulfur, it will take 24 months for the soil bacteria to metabolize. Powdered sulfur, aka horticultural sulfur, will be metabolized faster. I would expect that there would be some drop in pH, that can be detected, by June 1 of the first year. You might see pH = 7.5 by the end of summer.

Can you give a guesstimate of time in zone 6?

The information given above is based on experience growing blueberries, here in Madison, Wisconsin. Agricultural sulfur is put down, on the soil surface, in a ring around the shrub, and covered with mulch. I have found that it takes 24 months for the sulfur granules to completely disappear. There are no critters that eat sulfur, the squirrels, birds, and bunnies are not interested. To my knowledge it is slowly consumed by soil bacteria, although I have not actually made slides and looked at the bacteria myself. Since the bacteria grow best at some level of soil moisture and temperature, it should be possible to speed up the process by optimizing these parameters, but I have not pursued this. I just put down the sulfur, mulch with shredded leaves, and let nature take its course.

Thanks for the answers. The type of sulfur I used was those little pellets made out of 90% sulfur dust and 10% bentonite clay.

I realize this thread is really, REALLY old but I just thought I'd interject a faster way to lower pH that mimics the action of the microorganisms in the soil without the really long wait associated with elemental sulfur.

This is just in case someone else has a situation similar to the OP and comes here looking for suggestions/ideas on ways to speed the process up.

Elemental sulfur is slow reacting because you must wait on soil organisms to convert it to sulfuric acid and the conditions for these organisms are reliant upon moisture and warm soil temperatures... this is a very slow albeit a very stable process that takes months to occur and years to completion (if prilled sulfur). To speed things up instead of waiting on the soil organisms to convert elemental sulfur to sulfuric acid... why not just start off with sulfuric acid to begin with?

Purchase a quart of battery acid from an auto parts store at about $7... it is pure sulfuric acid at a 33.5% concentration and nothing more. Mix it into (please not the other way around!) 5 gallons of distilled water to create a stock solution that is going to be about the same acidity and danger as ordinary vinegar. From this stock solution you can add about anywhere from 1 to 5 tablespoons to dilute it with a gallon of your own tap water targeting a pH of about 5 or so... not all that different from rain water really (5.6pH). The precise mixing ratio will need to be determined for each person because everyone's tap water is going to be different depending upon the mineral make-up. Just get some pH test strips and ball-park it. Then water your soil with it once a week until you begin to approach your desired pH. Careful not to try to lower the pH too quickly though as it will be quite hard on the microbes already in the soil as that soil life will need time to adjust. If you do the math you'll see that there's almost 1300 tablespoons of your stock solution available to mix with tap water, that's makes a lot of gallons of "acid water"... should be quite enough to get your soil to the pH you're targeting and then hold it there until the soil microbes working on the elemental sulfur can catch up. Good luck.

"Good luck." is right. Anyone messing about as described above will need all the luck they can find.

I bought a bag of fertilizer with "Biozome" in it, will putting that fert down on top of some sulfur on a plot you want to try blueberries on this fall, and maybe other acid lovers this coming fall, will that help, or not so much?

My soil is mostly 6.8 -7.0.

poaky... Not sure who you're addressing but if its me then...

I would say to get the soil tested first (a standard lab soil analysis will cost about $25) and will get you not only an accurate measurement of the current soil pH and the sulfur ppm but also the balance of the major cations as well as micros and CEC (cation exchange capacity) of the soil to be treated. Depending upon what those results are, you should be able to put together a workable approach to achieving your goals with success. If you just want to take a stab at adjusting pH without regard to balance of minerals available in the soil, there are many websites with simple charts that will suggest how much elemental sulfur you'll need to apply to drop pH from 7.0 to 5.0 (http://web.extension.illinois.edu/cfiv/homeowners/080818.html)

The biology needed to convert the elemental sulfur to sulfuric acid (or sulfate) is already in your soil... it just needs a soil temperature above 60F, some moisture and enough time. Just be aware that sulfate will strip away certain minerals in the soil and release (increase) others that are fixed at the higher pH and thus its a possibility some may increase to toxic levels (for the plants) as the pH drops below 5.5 Its a little like shooting in the dark at a target you know the general direction of its location... but really the best advice is to get a soil analysis first before attempting do anything to the soil. Sometimes if you do too much of the wrong thing to your soil, it can be very difficult and time consuming to undo... not to mention expensive in the long run.

If you intend to plant in the fall or next spring using elemental sulfur then you'll need to get it put down before summer. But if you decide to start planting this summer then my posting above becomes relevant to that situation. Sulfuric acid sounds scary and it is if its at 98% concentration... that will eat the flesh off your bones and then eat the bones (a good way to get rid of a dead body... I watch a lot of ID channel) but battery acid is no where near that powerful at 33.5% ...why you can immerse your hands in it without burning the skin (don't get it in your eyes though) and once its diluted into a stock solution (mix a quart of battery acid into 5 gallons of distilled water to make a stock solution) you can even drink it (I don't recommend it though... I also don't recommend drinking vinegar either). With my tap water 3 tablespoons of that stock solution into a gallon of our tap water here will essentially create acid rain (4.5 pH) minus the nitric acid component and with ground water minerals. Watering with this stuff will get you down to your desired 5 pH in a relatively short amount of time and allow you to keep it there while the biology in the soil works on the elemental sulfur you've added... so you can plant earlier and have your plants growing sooner.

Commercial growers do this routinely and many savvy gardeners as well... not to be confused with the few uninformed posters on these forums who are prone to spouting nonsense and fear without knowledge.

I knew a blueberry farmer here in central MO who was growing in neutral limestone based clay. His blueberry field was on a hill so he put a well at the top and gravity fed acidified and fertilized water through drippers to all the bushes. Best blueberry crops I have ever seen. Exactly what his proportions and final water pH and application frequency/rates were, I couldn't tell you, but this system is certainly feasible.

Extra note of caution, as alluded to above, never add water to concentrated acid, always acid to water.

Sulfur is a known fungicide so I would be careful in timing the application of sulfur to lower pH together with the application of a fertilizer that includes a lot of biotics, some of which will undoubtedly be fungal organisms. I'd apply the sulfur now in time for fall planting and wait to use the fert until next spring.

The use of battery acid or diluted sulphuric acid to lower soil pH startled me when I first heard about it.....and I am a degreed horticulturist!! It just sounds so caustic and potentially damaging :-) But if you read the science behind it, it makes complete sense. Would still be inclined to use agricultural sulfur first, just for safety sake and ease of application, but the acid is indeed much faster acting!!

Our soil is way too alkaline for potatoes, so last year I mixed some MSM in with the soil and had a good crop. My "crop" was 13 plants. MSM is a sulfur supplement intended for human consumption so is easily and quickly digested in the soil, too, I should think and therefore don't have to use much. These are my own ideas.

@toxcrusadr. I cannot disagree with what you say. Really, I don't know how it interacts in the soil.

@gardengal. Hi. I found, just by happenstance, your comment, as follows, from 2009:

While it is often used as a topical fungicide, it does not necessarily
follow that it is a uniformly acting fungicide when applied as as soil
amendment, killing all the valuable soil fungi. In many cases,
applications of elemental sulfur actually stimulate soil biology.

Where did you find info that changed your mind?

Wow, lottsa stuff to digest here, guys. I THINK kimmq has been on here for a while, Monomer, I am gonna skip the battery acid approach;. I will say that all of my soil is either 6.8 or 7.0 except for maybe a few plots which I have added lottsa potting soil or bags of cow manure (composted) I know it's hard for you guys to know how much sulfur for someone to add etc. I think that I'll buy some soil in bags and mix in some peat moss (acidic) (which I already have) and add some sulfur to it, and fill up a raised bed frame I just bought, and maybe even wait until next spring to add a couple blueberry bushes.

The fertilizer which I've bought contains some "Biozome" stuff, which is many different baccillus and other stuff included with the fertilizer, it was about $6.74 bag, so the same price as the plain ole 5-5-5 fertilizer at Wally world, that stuff is 4-4-7 or something similar. I really needed the acidity for Blueberries. If it all fails then I will just remove the soil blend and try something else in that raised bed. I will likely get a soil sample for the bed next spring and have it tested.

I am kinda afraid to the battery acid thing. So I'll use the sulfur that is for "Turning pink Hydrangeas Blue" or the other way around, whatever the label says on a bag of the garden sulfur.

By all means, don't do anything you don't feel sure of or uncomfortable doing... besides using sulfuric acid really doesn't apply to your situation since you are not in any hurry.... however I will suggest you start now with the sulfur since the conversion from elemental sulfur into sulfuric acid by bacteria and fungi is a slow one that will require a growing season.

I pulled up this old thread because I felt what I have to offer might have applied to the original poster's desire. This thread was from over 4 years ago. Two years ago I was in a situation of needing to lower pH but not wanting to wait and give up a whole season to plant so I began searching the internet for possible ways to accomplish this. Using sulfuric acid directly seemed logical but in searching for more technical information from people with actual experience while also trying to find specific descriptions of how to do this safely, all I seem to turn up was a lot of disinformation, myths that was the basis for scare tactics across amateur gardening forums.... but the real kicker for me in this confusing search seemed to be that this non-sense was coming from self-proclaimed "experts" (but aren't we all?) who had a strong bias without any actual experience (obviously this is because of their own biases preventing them from ever trying it in the first place which leads to a circular logic that gets you nowhere). Eventually I did manage to find some technical papers authored by agronomy specialists that spoke to the use of sulfuric acid in a professional context and several turf management (golf course grounds managers) websites and some farmer websites that spoke of it as accepted practice where their techniques did not apply to my needs because of the scale of the equipment and tanks and in some cases whole ponds being managed as the acid reservoir and in the end none of these internet resources provided specifics for a home gardener who was just seeking a way to employ this technique safely. Forums were of no use because of all the crazy "experts" spouting knee jerk fear reactions to the whole idea of using sulfuric acid in the garden (despite the fact that all our gardens already have sulfuric acid producers during active summer temperatures... bacteria and fungi both). Gardening clubs and cannabis growers and other forums dedicated to home gardening were almost a waste of time in this respect because of all the either negative or confusing tactics (talking about using acetic acid instead because its safer, etc) polluting threads but with no other resources to turn to I persevered and waded through those thread seeking the one posting that would enlighten me... 'til I finally manage to ferret out enough information from a few posters that actually have real experience using sulfuric acid in the garden to learn about using battery acid and how to dilute it and apply it that I felt confident enough to take the leap. I gave it a try and it works! its neither dangerous nor complicated though there are a couple caveats that should be mentioned... just a straight forward to-the-point posting that explains the use of sulfuric acid in gardening... and that's all my posting above was meant to do. So, if someone else should want specific information on how to do this from someone who has actually tried it they will eventually come across this thread and my posting... without a bunch of scary gibberish tied to it. It would have saved me A LOT of time and stress doing internet researching had I found just such a posting two years ago. That is all.

Oh and poaky... you may want to do a little bit of internet research yourself into the use of Aluminum Sulfate in conjunction with edible plants (blueberries) because of possible toxicity issues. I'm not claiming to be an expert but I have read some things... so check it out yourself before you make your selection on which product to use to lower pH for growing edible plants and read what's contained in the bag before you make your purchase. Good luck.

There are calculators to estimate how much sulfur to add. Although if you're trying to go a long way it might be good to do it in stages. Here is one such calculator:

https://garden.org/nga/calculators/index.php?type=sulfur

Hey momomer, I won't use the aliminum phosphate, I've heard it isn't good for Rhododendrons either which I love, so I'll use sulfur in the bags for plants, I have nothing to say about the pure sulfuric acid issue, but, I am in no hurry for results anyway, okay, I'll say this, I would imagine as long as you checked the PH before planting, I would think it would be safe, and maybe let it mellow for a month before planting. I'm definitely no expert.