Turf grasses will not grow well in highly acidic soils. Acid conditions in lawn soil can occur due to overuse of nitrogen fertilizers; introduction of excessive amounts of organic soil conditioner, such as compost or peat moss, and by needles dropped from evergreen bushes and trees.
Acidic soils are commonly referred to as “sour,” whereas alkaline soils are called “sweet.” Extremes on either end are not good for turf grass.

Hopefully you remember a little something from middle school chemistry and testing pH levels: remember that pH is measured from 1-14, with 7 being neutral?
Just like liquids in the chemistry lab, soil with a reaction of less than pH 7.0 is acidic and soil with a reaction greater than pH 7.0 is alkaline. Most turf grasses grow best between pH 6.5 and pH 7.0. (finicky little buggers those grass blades are!)

If you have large bare areas of your lawn that are getting plenty of sunlight but just won’t support turf grass, you may consider asking your lawn care service to perform a soil test and see what may be going on beneath the surface.

What’s lime anyway?

Lime is a compound of calcium or calcium and magnesium capable of counteracting the harmful effects of an acid soil on lawn grasses
 

Functions of Lime
Lime is NOT a fertilizer, but more of a soil amendment or conditioner. Here’s what it helps with:

• Corrects soil acidity (obviously!)
• Furnishes important plant nutrients-calcium and magnesium
• Promotes availability and use of major plant nutrients and micro nutrients. It’s like greasing a wheel… it just makes things run through more smoothly.
• It increases bacterial activity in the soil which promotes more air exchange, thus aerating the root system. (It’s all microbial and stuff like that!)

Time of Application
Applications of lime on existing lawns are best applied in Fall and Spring because of cooler temperatures and readily available moisture.