Most plants tend to thrive somewhere in the middle of the pH scale, which measures soil acidity or alkalinity. If the soil is at one extreme or the other, roots might be unable to absorb the nutrients and minerals that they need. Lawn grass tends to prefer soil that is slightly acidic. To make sure soil conditions are just right for an optimum green lawn, you may need to perform a pH test on your soil and amend it accordingly to achieve the desired balance.
Perform a soil test with a commercially available testing kit. These kits are available at most garden centers and home improvement stores and generally cost from $5 to $40. Follow the directions to test the soil, which usually involves either sticking a probe into the soil or taking a sample and mixing it with chemicals.
Take a reading. The ideal pH reading for most lawns is 6.5 or 7. The pH scale ranges from 1 to 14.
Thoroughly rake the area in which you intend to plant your lawn. Remove all debris, such as rocks or roots.
Amend the soil with a spreader. If your soil has too much acid, you need to neutralize it by adding lime. Ground agricultural limestone is readily available at garden centers and home improvement stores. If your soil has too much alkaline, then use aluminum sulfate or sulfur, both of which also are readily available at garden centers and home improvement stores. How much you use depends on how far away from neutral your soil is; follow the directions on the package carefully.
Rake soil thoroughly. Both limestone and aluminum sulfate or sulfur need to be worked into the soil to take effect.
Water thoroughly and let the dirt sit for a few days before planting your lawn.