Jonathan Green Mag-I-Cal Plus for Lawns in Acidic & Hard Soil helps raise soil pH and loosen hard compacted soils to allow water and nutrients to penetrate deep into your lawn?s root system. Healthy lush lawns thrive in soils with slightly acidic to neutral pH levels ranging from 6.2 to 7.0. When soil pH levels drop between 4.0 to 6.0 this creates an environment for weeds to thrive and grows a lawn full of light green unsightly grass. Mag-I-Cal Plus contains calcium carbonate a completely soluble form of lime that is immediately available to adjust soil pH upwards. Poor soil is often the problem in growing a great lawn and calcium is vital to many grass plant functions. Where it may take several bags of lime to adjust low soil pH Mag-I-Cal Plus for Lawns in Acidic & Hard Soil has the power to do it all in just one easy application! This product also helps to break up clay and compacted soils.