Test Your Soil Before You Start
Soil must have the right pH in order for grass seed to germinate and grow. The pH scale ranges from zero to 14, with 7.0 being neutral. Grass will grow best in soil that has a pH between 6.0 and 7.5.
A DIY soil-testing kit can be purchased from most nurseries or home improvement centers. Follow the manufacturer's directions to test the soil. For most kits, you need to mix a little bit of soil and water in the kit’s plastic vial. Shake vigorously and wait for the mixture to change color. Compare the color of the water/soil mixture to the color-coded chart printed alongside the vial to discover the pH of the soil.
If your soil is too acidic‚ below 6.0‚ add pulverized lime to raise the pH. If the soil is mildly alkaline‚ 7.5 to 8.0‚ you can balance the pH by mixing peat moss into the soil. If the soil is very alkaline‚ over 8.0‚ lower the pH by adding sulfur.