Even if you get your soil pH corrected, your water supply may be quite high in pH, so the actual problem may be the water you are giving the plants. You can check your local municipality's water quality report to get an idea of what the pH is. You should be able to find it online.
Assuming you are hand watering your plants daily, you can start using a liquid fertilizer intended to be added to daily waterings. There are a number of them out there and you can find them either online, your local hydroponics store, or sometimes at garden outlets. Wherever you find such fertilizer, you can also find liquid CaMg. This will raise both the calcium and the magnesium of the source water, and the directions are right on the bottle as far as how much to use.
Once you have your watering batch mixed, you can lower its pH with a few different methods. One of the cheapest is hydrochloric acid sold in pool supply stores as muriatic acid. One gallon of this stuff goes a long ways. Roughly 1/4 cup of this stuff will lower the pH of a 55 gallon drum of water by 1 or 2 points. So you'll need a method to measure pH of your water. You can get a pH testing kit at pet supply stores. I have a digital pH meter which wasn't all that expensive and makes life a lot easier if you are using it often. You have to calibrate the digital meters often, like once per week, so you'll also need a bottle of calibration buffer if you get one.
= new reply since forum marked as read