Shopping Tips

• Have your soil tested by your local USDA Cooperative Extension Service to determine pH and what nutrients, if any, your grass is missing, or test it yourself with a soil testing kit.

• Once you know the pH, you can add organic matter to help balance it. Lawns prefer slightly acidic soils with a pH range of 6.5 to 7, but flowers, shrubs and trees vary in their pH preferences. Lime helps balance acidic soil, while sulfur helps with alkaline.

• To find out the nutrient content of a fertilizer, look for the "NPK" number (NPK stands for nitrogen, phosphorus and potassium). A "5-6-5" NPK number, for instance, means that a fertilizer is 5 percent nitrogen, 6 percent phosphorus and 5 percent potassium with the remaining 84 percent representing filler material.