Benefits of Lime
Fred Newcombe

It’s fall so, like many landscapers, you’re probably getting ready to start liming. Although, what are the benefits of lime?

Liming provides three potential benefits important to growing healthy turf:

  • Improves Soil Chemistry
  • encourages Beneficial Soil Biology
  • and Improves Soil Structure.
Improve Soil Chemistry

The function of lime is to raise the pH of the soil. Soils with a pH below 7 are deemed acidic; while soils with a pH above 7 are deemed alkaline. Soils tend to be acidic in the Northeast and become more alkaline as you move west. A pH of 5.0 is ten times more acidic than pH of 6.0; while a pH of 4.0 is a hundred times more acidic than that of pH of 6.0. Turf grass grows best in soil with a pH of 6.5 – 6.8. Soils in this range encourage root growth and make more nutrients available to the grass. Soils with pH 4.0 – 5.0 tend to be similar to those of our forests. As such they are more conducive to growing white pines and oaks than turf grass.

Encourage Biology

pH affects microbial activity. Soils that are more acidic tend to be fungal dominant. Soils that are in the 6.5 – 6.8 range tend to be more balanced between fungal and bacterial activity. Encouraging this microbial activity contributes to the availability of nitrogen, sulfur and phosphorous in the soil.

Earthworms are also affected by the pH. They need the pH to be near neutral for their sticky mucous or slime. The slime has several purposes, including allowing the earthworm to breathe through its skin. The slime also acts as a lubricant; facilitating their burrowing. The slime also helps to form soil aggregates.

Improve Soil Structure

The formation of soil aggregates helps to improve the soil’s structure. The addition of calcium through the liming process also helps improve soil structure. Calcium and magnesium stabilize soil aggregates via the formation of organic matter – clay bridges. Aggregate stability improves the soil’s porosity and tilth.

How much and What Kind of Lime to Apply?

Often, not nearly enough lime is put down to either help or hurt the soil chemistry. It is critical to soil test with a reputable laboratory for pH, buffer pH, Calcium and Magnesium to determine how much and what kind of lime to use – dolomitic or calcitic.

For more on lime available through PJC and outsourcing soil testing.