One of the biggest secrets to having a lush green lawn lies underneath: soil with the proper pH.

"Getting your proper pH for the soil in your lawn is really more important than putting seed on" said Consumer Reports' Peter Sawchuk. "Because when you have the proper pH, your fertilizer works better, it lasts longer, and you get much healthier grass."

Consumer Reports' Peter Sawchuk evaluated six home soil-test kits designed to measure the pH level.

"A pH scale consists of numbers from 0-14, with seven being neutral. Lawns require a pH of approximately 6.5-7." said Sawchuk

Testers took dozens of samples at seven different locations. They also sent soil samples to two outside laboratories to confirm the soil pH. Those results were then compared to the home test kits.

"Unfortunately they weren't all that accurate. They were inconsistent. So they're not the best choice for determining your soil pH." said Sawchuk

Instead, Consumer Reports says you can have testing done by your local cooperative extension, a private lab or a lawn-care service.

"Soil in the Northeast and Midwest almost always tends to be acidic. And the correction for that is to use lime. The best lime to use is the pelletized version, which is easier to handle and it also lasts longer." said Sawchuk

Soil in many parts west of the Mississippi and in Florida tends to be alkaline. TO solve that problem, you'll need to put down sulfur, or its equivalent, to get your solid to the proper pH.