Lime applications are necessary at least once per year here in Newfoundland.

What is Lime for?
Dolomitic Limestone (Calcium Carbonate) applications are used to increase and neutralize the pH in the soil. The soil in Newfoundland is notoriously acidic, particularly sod farms where the sod is grown in the bog, and needs a steady diet of lime in order to grow healthy, lush lawns. Important plant essential nutrients that are unavailable under acidic soil conditions become available to the plant as the soil is neutralized.
Dolomitic limestone is natural and is safe for humans and pets.