The sulfur will take several months to change that soils pH and it is difficult to guess how much might be necessary to lower that 6.5 pH to the 4.5 to 5.5 pH range Blueberries prefer to grow in. Since it can take 3 to 5 years after planting for those bushes to start production you have plenty of time and planting them now will not be very harmful.

Your best course of action right now is to contact your states Ag School (university Cooperative Extension Service) and have a good reliable soil test done specifying that Blueberries will be grown in that soil and they will provide you with the information you need.

While I have seen much about using Vinegar for lowering soil pH I have not yet found which, salad dressing (about 5 percent Acetic Acid) or horticultural (about 20 percent Acetic Acid) to use. Most everything I have seen says to add 1 cup of vinegar to 1 gallon of water, but nothing about the strength of the vinegar or how much which one will lower the soils pH.

Blueberries are bog plants and need a lot of water, although they do not like the roots in really wet soil. Evenly moist, yes, but not real wet. Since bog soils are naturally acid that is one explanation why Blueberries like acidic soils.

kimmq is kimmsr

jared, there are some clues in your post that indicate that you may be located somewhere in the PNW......is that correct? If so, you may not need to manipulate your soil quite as much as you think. Can you get back to us on that?

The bushes are mature and flowering/starting to produce berries.

I am located in Washington. Below/outside the soil in the bed it is more acidic (I have rhodies and hydrangeas growing all over) but after a year the soil in the bed has not really lowered its pH by much.

OK, that confirms my thoughts :-) You do not need to lower the pH so drastically. Blueberries grow just fine in our native, moderately acidic soil, as the number of local commercial blueberry farms and a whole lot of home gardeners will attest. You can add the sulphur although that will take time to become effective. My suggestions for the meantime include adding the peatmoss - a couple of bales for that square footage should be more than adequate - or locate an acid planting mix to add to the bed. Local nurseries carry a couple of Kellogg products under this labeling. Look for Gardner&Bloome or Master Nursery as brand names.

You can fertilize your blueberries with cottonseed meal (a natural acidifier) or any standard rhody and azalea fertilizer. This will help to keep the pH at the appropriate level.

I would go ahead and plant the bushes ... the domestic varieties are far more tolerant of soil pH than wild-collected ones, so as long as you aren't planting in desert acaliche they will \be OK. They require moist well-drained soil, high in organics, of course, so add any finished compost you have.

"Espoma states 12lb/100 sq. ft. to lower by 1 pH." (in an unspecified soil type - some are easier or harder to correct) ... use 6lb and till it in. You don't want to overcorrect the pH.

Plant them, mulch heavily and keep the bed evenly moist. Test again in the fall and see what happened. And look at the bushes - are they happy?

Make a compost heap with all that stuff you mentioned and add it to the bed as you need it.