I believe you can use coffee grounds.

Others may disagree but to me vinegar is just a temporary stop gap until sulfur kicks in. I'd try to figure out how much sulfur is needed for your soil to lower the pH the desired amount. Work that into the soil. By fall you should be in better shape.

Tim- do I put the coffee grounds in the soil to mix? What kind should I use coffee grounds? Roasted, dark coffee, etc.. What kind of brand name? Would they really help a lot to decrease pH?

Fruitnut- I see, but would vinegar help water to make acid and prevent to increase the soil from water? I think my water is 7pH. It is a city sewer if that helped you. Use peat moss and garden sulfur to mix in the soil, won't that hurt cranberry? Or is it just too much? What it is usually take the soil to adjust to acid soil? 1 year?

There are several ways of lowering soil pH. The problem is, what is the starting pH, and what is pH after an application?
Soil testing labs use pH meters, but these cost between 50 and 500 dollars, and they must be calibrated with standard solutions before use. The best way I have found for measuring soil pH is indicator dye. A 2 dollar bottle of indicator dye solutions might do 100 tests. Since cranberries grow best with soil pH between 4.2 and 5.5, the appropriate indicator dye would be bromocresol-green, which turns yellow at pH=3.8, and blue at pH=5.4. How much sulfur to use depends on where you are starting from. If you have tap water from municipal water supply, there should be an annual water quality report available, and this will give the water pH. If there is limestone in your area, your native soil might have a starting pH over 7.

Eric- hmm, where do you buy indicator dye? Wouldn't pH meter testing help? You just put it in the ground and turn ph on then they will tell you. I'm not sure what they are called but I have it, it only costs around 10 dollars. It can be found at garden stores. It also has moisture meter. It will let me know how much they are dry or wet. I'll need to ask my family if their bills have record of water ph. If not then I can take them to Martin's plumbing. They will test it at no cost.

If you live in a city with a public water supply, the water authority will mail out an annual report, and this will contain a pH measurement for your water. I don't know if the meter you have will give accurate results. The pH meters I have used in the past are made to work with aqueous solutions, and they must be calibrated before use. The calibration step also confirms that the meter is working. The indicator dyes that I use for pH testing are available at scientific supply stores, places that sell laboratory supplies.

We are not actually live in the city but we have water sewer. They were just added to our house. I see, what are they usually at price?