Fertilisers and irrigation can leach alkaline components from the soil, leaving it with a pH below 7.0, also known as "acidic soil." If you have acid soil in your lawn you will need to add lime. Not only does lime correct the pH of the soil, it imparts calcium and magnesium, which are generally lacking in acidic soil. Lime is available at nurseries and garden centres, in powdered or pellet form. The pellets emit less dust and are easier to spread, but both require that you wear a dust mask and gloves during application. When purchasing lime, choose dolomitic lime if your test results show a need for magnesium as well. Otherwise purchase calcitic lime. The best time to apply lime to your lawn is in the fall.
Test the pH of the soil to determine how much lime to apply to the lawn. You can use a home testing kit, available at gardening centres, or have the soil professionally analysed at your county cooperative extension office. The extension agent can help you determine how much lime to apply to adjust your soil's pH.
Don your dust mask and gloves.
Pour the suggested amount of lime into the spreader and walk briskly, spreading the lime evenly over the lawn.
Water the lawn as you normally do to dissolve the lime into the soil.