sooby said: ... Elemental sulfur is the usual way to lower soil pH but the amount to use depends on whether your soil is sand, loam or clay. ...
Was your soil test done by a laboratory? If you have access to agricultural advice and testing your best bet would be to ask them what you can do because they will be familiar with your soil type and how likely it is that you would be able to adjust the soil for blueberries.
I agree with both: acidify soil with pure sulfur, but expect it to take some years to change the pH that much, especially down deep. You need a BIG pH change, so you probably want a strong and cheap acidifier: elemental sulfur.
Pure sulfur ("elemental sulfur", "flowers of sulfur", "agricultural sulfur") is gradually consumed by aerobic soil microbes whose names I forget. They use the sulfur as FOOD (at least, as an energy source and electron acceptor).
Unless there are impurities in the ag sulfur, it doesn't release anything toxic, just acidity and sulfate ions. I assume it is approved by "green" and "organic" certifying authorities.
http://blueberries.msu.edu/upl...
http://ohioline.osu.edu/agf-fa...
http://ohioline.osu.edu/agf-fa...
"To convert the recommended rates from pounds per acre to pounds per 1000 ft2 divide the values in Table 1 by 43.56. "
I seem to see people suggesting sulfur or iron sulphate or other things based on what OTHER deficiencies your soil might have. Thus getting a good soil analysis, especially of the deep soil near your berry bushes, could help you pick the best acidifier.
The soil microbes oxidase sulfer the same way we oxidize sugar to CO2. They oxidize Sulfur to the acid form of sulfate (technically, sulfuric acid, but it never exists as pure sulfuric acid (H2SO4)). As each molecule is oxidized, inside the bacteria, it combines with water and ions near it to release its acidity and become simple sulfate ions: HSO4- or SO4--. And sulfate is a required plant nutrient.
Also, this article claims, cleaner air and purer fertilizers are making sulfur deficiencies more common in many soils:
http://www.agweb.com/article/t...
