Not wise to use battery acid. It's dangerous to handle. You don't know how much to dilute it. And even if you did, the effect would be rather temporary.

Instead, use agricultural sulfur. It's best to mix it into the soil before you plant.

But you can apply to the soil around established plants, then scratch it into the surface of the soil; repeat every 2nd to 3rd year. If so, be cautious because roots of blueberries are quite shallow.

I love your thread title thisbud4u. I'm just up the coast from you, and have the same problem water. Actually, battery acid is just over 33% sulfuric acid, and one of the best acids to use to acidify water for plants as you obviously know (assuming traditional safety procedures are used). Its one of the main acids the ag pros use. Its not advised for those who are afraid of such things of course, or those who dont have chronic alkaline water as some of us in the southwest do. As with any acidification process, a pH meter or indicator paper is essential for correct dilution. Or a good chemist friend :-). 2T of acetic acid reduces one gallon of our water to a pH of around 5.

I however do not know if there are impurities in battery acid. (That name is certainly duanting!) That is something I want to know too. Sometime this week I'm going to the auto store that carries it and see what I can find out. Some of those car people are quite particular what goes into their babies. I'll let those who are interested know what I find out.

Some hydroponic people use battery acid for pH control too. Other acids suggested for use around plants are acetic and citric (neither of these are long-term solutions) and sulfuric and phosphoric acids, with sulfuric being the best choice.

Note: using acid for plants is not for anyone who is not experienced using strong chemicals. They can be very dangerous. If you even have a small hesitation, dont even think about using them. And never use if there are children or animals or anything that might distract you. This is serious business.

That said, I finally got to the auto store today and got a 6 quart container of battery acid (33% sulfuric). It comes in a cardboard box with a flexible bladder inside that has a cap with a tube inserted in the cap, and a clamp on the tube. And directions about how to use the box.

I asked the clerk (a very nice man who was interested in what I was going to use it for) if the B.acid was pure. He said it was because impurities would decrease the life of a battery. The label says sulfuric acid and water as ingredients.

Since this thread was started, I have read in several places where others have been using sulfuric in the form of battery acid for their plants. Sulfuric apparently is the best to use in areas with lots of calcium in the water since it turns the calcium into inert gypsum, unlike vinegar or citric acid which are not permanent solutions.

The first thing I did (after putting on safety gear and go outside, etc.) was make a dilution down to 3.3% acid by adding 1 cup acid to 9 cups water for a stock solution. (never add water to concentrated acid, it can be explosive). Then I added 1 tablespoon of that dilution to a half gallon of my water (the same dilution of 5% vinegar that gives me Ph 5). The pH of the original water was 8.4. After adding the 1T acid, pH was just over 2. I brought it to around 5 by adding more water. I do not have exact amounts so I will have to do it more precisely next time. I also would like to do this with a better pH meter next time too, or some test paper.

I watered my blueberries with this final weak solution. I'll let you all know what happens to the plants. :-)

Sweet Lemon, Thankyou EVER so much for doing the research. You don't mention how much water you added to bring the pH up from 2 to 5. That would be critical. As I've said before, I prefer using fresh pH paper--gives more reliable test results than most pH meters, which tend to go off calibration in the most finicky ways. Also, please let us know, down the road, how your plants responded.

Note to ericwi: Sweet Lemon mentions in his last post that sulfuric acid is better than acetic acid for regions of the country (like yours in Wisconsin) where there is alot of dissolved calcium in the water. If we can get this sulfuric acid treatment down to a science, you might want to take this up as an alternative to the vinegar/acetic acid which I recall you mentioned that you add to your irrigation water for blueberries.

I didnt mention the final dilution because I dont know what it was. I was surprised by the low pH of sulfuric compared to the same dilution of vinegar even though I knew one was a much stronger acid than the other. When I added even more water, at that point, I knew the amount, but still the pH was too low. So I added more and forgot to keep track so I cant tell you. I am thinking however that adding one cup of 33%sulfuric (battery acid) to a gallon of water might be a better beginning stock dilution judging by yesterdays experiments. Then diluting from there for plant usage. If my pH meter can be trusted that is. I would rather begin with a weaker solution so any final measuring mistake wont have much impact on the plants.

I really dont trust my pH meter and would like to get some fresh pH paper. I've looked just a bit locally, but havent found any. The site you mentioned in another thread requires registration of personal information before even finding out what prices are. I would like to find a small amount of full-range test paper locally. Once I get a final formula, I dont think constant testing will be necessary since I doubt our tap water pH would vary that wildly. And I really do prefer letting my plants tell me what is going on, but this is still too soon in the acidification experiment for that.

It is also looking as if this sulfuric acid acidification is more cost effective than using milder acetic acid. Here the cheapest white vinegar at 5% that is available is $2.59/gallon at costco. "IF" one can get the equivalent pH change of 24 gallons of acetic acid from 1, 6 quart container of B acid for $15 plus tax, that is quite a savings for a better (though much more dangerous) product. Again, IF that is the final dilution, which I really dont know yet.

Oh yes, the plants I watered well with yesterdays solution are still looking very healthy. :-)

(And again, dont use strong acids unless you use adequate safety precautions mentioned here and elsewhere - eye, skin, clothing protection in a well ventilated area, with plenty of fresh water available for emergencies, and never pour water into concentrated acid - it will react suddenly and dangerously. Its acid into water - A before W))

SL, I see what you mean about being cost effective---a tiny amount of sulfuric goes a long way. Also, good advice about creating a weak stock solution from which to make further dilutions. In order to do this really correctly, you might want to use a graduated cylinder or a pipet, so you can add really accurate amounts of acid to the water. (obvious precaution to anyone trying this---don't pipet by mouth!).

To all, SL's advice on diluting acid correctly is of the utmost importance, as is the general advice to wear glasses, rubber boots and still be extra careful with the stuff.

The downside to this discussion is the danger. The upside is the cost savings. The real test would be to take some blueberry plants that were unhealthy due to excessively high pH, and add the correct dilution of sulfuric acid and see whether the plants return to health, and how quickly. Another advantage of this method is that the acidity works immediately. For the record, there's another thread I started which I called "calling all chemists" and after much discussion, I finally did the correct experiments and found that iron sulfate acidifies immediately. The same would be true for ammonium sulfate, or even aluminum sulfate (but blues don't seem to like aluminum). The sulfuric acid treatment would be most applicable for those circumstances when you don't want to add more of the counter ion (iron or ammonium).

I'm quite excited about this acidification process. I think it will another effective tool in the constant battle with alkalinity some of us in the dry west have when trying to grow things. Our city water is rainwater collected in dammed lakes over the winter and held for months in the hot sun with large amounts of evaporation. In years when there is little rain to replenish the lakes, the dwindling water supply really gets bad. Ack. You really cant drink it because it tastes so bad with all the dissolved minerals. I envy those of you who have ample nice acidic rain over the summer. That would make a blueberry growing life so much easier.

I also use sulfur and iron sulfate, both of which are good to acidify. Sulfur takes a long time however, and in our water, no matter what the pH of the medium in which the plant roots grow, esp in containers, the high pH of our horrid water needs constant attention. I even add mild acid to the rinse water of the laundry for better results.

I did read the 'calling all chemists' thread, and just about every other thread on blueberries here that a search turned up. Fun reading, I learned a lot.

I ordered some pH indicator paper from ebay. It's been shipped and should be here in a few days. The pH range is 4.5 to 7.5 or so. With shipping it came to about $6-7 for a 15 foot roll, not in a dispenser. There were also indicator strips that were interesting, but the colors in the lower pH seemed easier to read with the paper. Till I get the paper, I'll water with the vinegar treated water since I really dont trust my pH meter that much. Wouldnt want to damage the plants by not waiting for just a few more days. It will be good to get an accurate reading on these dilutions, as well as a way to periodically monitor the water once the basic formula is found.

Eventually I am planning on mixing batches of water in a garbage can with the proper pH and any soluble fertilizers, and then using a submersible pump (plugged in a safe gfc outlet) to deliver the water to the containers.

Growing blueberries is worth all the hoops some of us have to jump through!

I got my ebay indicator paper yesterday (pH range 4.5 to 7.5) and started experimenting. I do not yet have our final easy dilutions, but they are in the ball-park of what our schitzoid pH meter had been telling us. With personal safety in mind, I previously had made a weak stock solution of 1 cup of battery acid added to 15 cups of water to total 1 gallon. I cannot measure what the pH of this is because it is lower than the paper indicates.

With a series of dilutions, I finally got to about 5 teaspoons of this solution added to a gallon of tap water to get to a pH of around 5. Indicator papers are not that exact. Since the base color reaction is 4.5, I went for a dilution showing the very first change of color as my goal. I have 15 feet of the stuff, and lots of time ahead to hone it further. I am cutting very very tiny pieces of the paper and using cleaned fine tweezers to hold the slips for the tests, then holding them against a white background. This is not a difficult thing to do.

Keep in mind my original measurements might not have been that accurate. Next time I will do what thisbud suggests and make very accurate measurements. I want to get to a dilution of some sort that is in very even, easy to use increments such as 1 tablespoon to a gallon in our water. Or 2 cups intermediate dilution to a 32 gallon garbage can. I want to be able to easily measure a specific amount of acid, then add it to a known amount of water since this will have to be done several times/week. Of course your water will be different than ours, and it will take a lot of testing to get there.

I just read in an article from a link lucky_p sent in another bb thread that the local blueberry ag people in my state (california) use water acidified to a pH of 5.

In the end, I think this will bring the cost/semi-diluted gallon to just over $1, compared with $2.59 for vinegar at costco.

(When using acids, please follow all the safety precautions that come with the product. This is not child's play.)

While I'm neither recommending nor cautioning against the use of sulfuric acid to acidify water for BBs, I will issue a caution for folks considering diluting battery acid for this purpose - Always add Acid to Water - not Water to Acid - Adding water do the concentrated acid solution can generate heat and splattering/spewing, which could result in injury/damage to your person.

Here is a link that might be useful: Acid to Water

As an FYI, according to this, straight battery acid (33.5 % sulfuric) has a pH of 0.5.

I have a queston: why not use pine needles for your blueberry compost? This acidifies, is free from your neighbors with pine trees if not your own garden, and is what would acidify the soil for your blueberries in nature. I suppose the drawbacks are mess and patience. Are there other drawbacks? I mean, it seems like it would work to me.

Even though its in the common information exchanged in forums, there is now conflicting information in studies as to whether decomposing materials such as pine needles and tree leaves acidify the soil sufficiently enough for blueberries in all areas.

Some of us who are considering regular acidification of water tend live in dry environments with alkaline water. Even if the growing medium is acid enough, straight peat even, when you continually add water at or over a pH of 8, it will bring up the total pH available for the plants, and then they dont do very well.

Believe me, I would really prefer to do something easy and to not have to work with sulfuric acid. Its not my idea of a hot date, but with the available information, it seems the most efficient, cost effective way to maintain a low pH for successfully growing blueberries. In some warmer, drier parts of the country its easier to grow our blueberries in pots, and that requires frequently watering daily. This is the situation where additional acidification is essential for success. Those of you who live where this isnt necessary are very lucky.

Interesting thread...My question is, why must you have blueberries at all? Especially when you have your pick of so many luscious fruits (nectarines......). We are lucky enough to have wild blueberries growing all around the edges of our property but I don't expect to grow bananas in Nova Scotia.

Let's see, there's the antioxidants, touted as being very healthful, and then there's the blueberry pie, and the blueberry muffins, and the pancakes, and the....life just wouldn't be the same without blueberries. Wild blueberries growing all around my property, now that's a dream devoutly to be wished for.

We also can grow all the citrus fruits too. :-) I guess its human nature for some of us to try to grow what is a bit more difficult.

Once you get the right formula for the right varieties, growing blueberries in the s.west can be actually very easy in many senses. There are commercial bb farms both to the north and south of us, so they can be grown successfully here. Why not in he home garden too?

With the flood of new low-chill varieties coming out the past few years, its just plain exciting to grow them at home. I havent been this enthused about growing a particular fruit for years. I may complain here and there, but frankly, figuring this out is fun.

It was the battery acid idea that gave me pause. Would I use bleach to get alkaline soil in order to grow pomegranates? (Maybe not a good comparison). Of course I understand about the flavour.....

I know what you mean. The very words 'battery acid' conjure all sorts of negative images. They certainly did for me the first time I read about someone using it around plants (eek!), but its really just a relatively inexpensive source for sulfuric acid, new, not drained from a used battery. When greatly diluted, it is beneficial to plants that require a low pH. People sprinkle lime all the time to adjust pH upwards, so why not use something to adjust the pH in the other direction too?

Yesterday I filled a garbage can with tap water and allowed the chlorine to vaporize. Today I added a small amount of ammonium sulfate and some of the intermediate dilution of battery acid (always use safety gear and safety precautions- see previous posts in this thread), and brought the pH to about 5 using indicator paper. I then watered my container bb's. A lid covers the g-can so no moskies breed and there should be little evaporation to change pH, though I will check just to see. I do not have specific dilutions to pass on, and wont until this gallon of intermediate dilute b. acid is used up. Stay tuned.

It was the battery acid idea that gave me pause. Would I use bleach to get alkaline soil in order to grow pomegranates? (Maybe not a good comparison). Of course I understand about the flavour.....

No. You would use lime. Bleach won't get you anything but dead plants.

I suppose if I have to ask, then I am not an experienced enough chemist for this but... What are storing your gallen of diluted stock in sweet lemon?

I dont remember all the info that is in the thread above, but what I am doing now is adding 1 cup of straight battery acid to almost one gallon of water (using a non-reacitve plastic funnel), then filling it to the top with water. By the time its been diluted that much, topping off the gallon with water is not dangerous.

Depending on how much tap water is in the garbage can, I add about 3 cups of this to a 2/3 full garbage can, then test the well-mixed water with acid indicator paper. I use an old oar that I got at a yard sale to mix. This garbage can has a leak near the top so I'm planning on getting a new one so the amount added will be very uniform. Every time I also add 4 measuring tablespoons of ammonium sulfate or -less frequently- a combo with miracle grow, etc to each garbage can of water. No leaf burn what-so-ever. Just nice, well-formed green leaves and actively growing plants. (my apologies if I am repeating myself - I dont remember what I have written where.)

I am using an old vinegar plastic gallon bottle with a non-reactive plastic lid for this stock solution. It is stronger than a gallon water bottle. I do not allow it to be exposed to the sun since these sorts of plastic bottles will break down in the sun. Glass would be good too, but I dont like the idea of something breaking outside. I also have 2 sturdy PETE (# 1) clear plastic cranberry juice gallon bottles from costco that I am going to use too. I'm planning on mixing several stock bottles at once so I dont have to do it too often.

I water my full-sun blues in pots (with mulch) about every other day thru the summer. Less in winter, daily if over 90 and/or windy, but that is rare. On infrequent occasions when they need water, and I'm in a rush, I will use tap water from the hose.

My plants are absolutely thriving on this treatment by the way. Other than using a potentially dangerous chemical, I have no regrets about this technique at all.

Just make sure if you use a strong acid such as this, that you follow the directions on the package, never add water to straight acid, wear protetive clothes and eyewear, do it outside, etc etc.

ps. I store the partially used battery acid container itself, (which is a 6 quart bladder inside a cardboard box, with a tube spiggot with plastic clamp,) inside a larger waterproof plastic kitty litter container with lid. This I keep outside under a tree in total shade. There are no children or pets around.

I am using a method similar to sweet lemon, but instead of battery acid I am using Muriatic (hydrochloric) acid, packaged for use to lower the pH in swimming pools. I make my Âacid water in a rugged 44-gallon plastic drum, filling it up with about 40 gallons of tap water (tap water here in the SF Bay Area reads about 7.5). To that I add 3-oz of acid (sometimes a little more) and that brings the pH down -- according to my meter -- between 4 and 5.

IÂve used wide-range pH strips, but can never seem to get an accurate color reading for the pH of 3, 4, or 5 (the numbers I need the most accuracy on -- go figure), so I have basically given up on using them. The meter, although the instructions say not to use in water, seems to give accurate results.

So far, all 33 or so of my in-ground planted blueberries seem to love this special low-pH water. But does anyone know if using Muriatic acid can be harmful to them in the long run? Perhaps I will try the battery acid next, since it seems to be the more ideal acid to use.

I am a bit late on responding to this thread. I have found it very, very informative and wonder how all your plants are doing. I am growing about 400 or 500 african violets and am considering this method for lowering the ph in my watering/wicking trays. How long acting is sulfuric acid compared to the other acids?