I found all of this on a different site. These are all usable.

Fertilizer:

The majority of fertilizers are high in ammonium nitrate, ammonium sulfate, and/or sulfur-coated urea because of this fertilizing soil will gradually change its pH. This is not a quick fix, but it is a good way to slowly make soil more acidic which can make it far easier not to over shoot.

Sulfur:

Sulfur can be purchased in various forms in gardening supply stores and nurseries. Though faster than the above mentioned methods sulfur is also rather gradual and may take several growing seasons for large plots of land if you need a dramatic pH shift. As an example adding 1.2 oz of dusting sulfur to sandy soil (sand requires less sulfur to alter pH) or 3.6 oz to regular soil per square yard will reduce soil pH one point. You generally should not attempt to change soil pH more than one point per season with this method. The sulfur you purchase should have precise directions for its particular use.

Vinegar:

This is a quick fix and works especially well in container gardens or pots. Add two tablespoons of vinegar to a gallon of water for watering. Be sure to monitor the pH change closely as this method is easy to over shoot with.
silent leprechaun Reviewed by silent leprechaun on . Need help with ph I messed up my plant has some leaves turning yellowish brown in spots and some are curling up some lower leaves have died completely and I barely started flowering a week in I checked the Ph and in my soil it is at 5.8 so my question is what I do to bring it up to at least 6,7 or 6.8 any help is appreciated Rating: 5