Lime and baking soda are compounds for lowering PH, but I am hardly an expert. Do you know the current PH of your blueberries? Are they in containers or in the ground?

Jason:

Please don't put any lime or baking soda on your bb. They will raise the pH and kill your plants in short order.

You can lower the pH of of your soil in pots by applying very acidic water but that's probably not the best way. No one can tell you how long it would take because it depends on how acid you make the water and the nature and amount of alkalinity in your pots.

You'd be better off applying iron sulfate and/or sulfur to the pots and then use rainwater or nonalkaline well water. The amounts in any of these are a guess. I use diluted battery acid to acidify my well water. But don't try that unless you know what you are doing.

Rainwater or acidified well water plus ammonium sulfate fertilizer keeps my potted bb at ~pH 5 last time I checked.

The Fruitnut

Jasoncoco,
the gurgler has it backwards, NEVER EVER ADD LIME OR BAKING SODA to your Blueberries if you want them to live! The fruitnut knows what he is talking about, just one thing, if adding sulfur to pots it is better to use just a small amount at a time and space the applications by several weeks or you may end up with a PH too low

Oops, yes I meant the opposite. Sorry

We have hard water here in Madison, Wisconsin. For example, our stainless steel teapot has to be de-limed every two weeks. I don't ordinarily use our tap water on the blueberry shrubs out in our yard, but every August, it seems we have a drought, and I am forced to water the blueberry shrubs with tap water. I have a pH meter, and using this instrument, I have determined that it takes 6 fluid ounces of white vinegar, from the grocery store(5%) to lower the pH of 4 gallons of tap water. Does your tap water contain dissolved limestone?

Thanks everyone. Im not quite sure if my tapwater contains dissolved limestone. i really didnt want to have to buy any sulfur or anything like that. I was just checking if i could lower the ph of water with ph down and maybe lower the soil ph that way. Fruit nut, would you suggest using rainwater instead of doing it this way. Or should i just go ahead and get some iron sulfate or alluminum sulfate.

Ericwi,
Vinegar won't work, it breaks down in the soil after about two days, I would use a small amount of ammonium sulfate in the water.

Jason:

Sulfur or iron sulfate should be your cheapest route. It doesn't take much. Definitely use rainwater if avaliable. I tend to agree that vinegar is not a long term solution. Battery acid, sulfuric, is permanent. I'd stay away from aluminum sulfate.

Sorry we cann't be more specific as to amounts. But a small handfull of Ironite or a tablespoonful or two of sulfur will change the pH of a 15 gallon pot quite a bit. Main problem with sulfur is it may take some time to be effective.

The Fruitnut

alright. I went ahead and ordered a couple pounds of iron sulfate. Thanks for the help.

I know, I know, "vinegar won't work." But the truth is, I have been successfully using it for about 10 years now. It works great. One time I used a garden hose to melt away a large mound of ice & snow that was covering a blueberry shrub. I forgot about the dissolved limestone in the water, and sure enough, that shrub had yellow leaves two months later. Multiple treatments with the tap water/vinegar mixture got the shrub back to good health, though it took most of the summer to accomplish this. I don't know why vinegar works for me, when everyone says it shouldn't. Perhaps it binds to the clay in our local soil, and never gets a chance to evaporate, like its supposed to.

I've never heard iron sulfate decrease pH. Iron ion and sulfate ion don't decrease pH. I use amonium sulfate becouse of amonium ion. It realy make pH lower. Sulfur is also effectiv. Rate of decrease of pH isn't fast. It could take one or two years (because of buffer properties of soil).

Here is a link that might be useful: My blueberry plantation in Poland

I was wrong, iron sulfate decreases pH.

Here is a link that might be useful: My blueberry plantation in Poland