We often hear about the importance of lime on our lawns; but what is it really doing?
Liming provides at least three benefits important to growing healthy turf:
- improves soil chemistry
- encourages beneficial soil biology
- improves soil structure
Ideal pH Levels
Turf grass grows best with a pH of 6.5 – 6.8. The function of lime is to raise the pH of acidic soil so grass wants to grow. Below and above this range fewer macro and micro nutrients are available. Both microbial and earthworm activity is affected by pH. Soils that are acidic tend to be fungal dominant while soils that are between 6.5 – 6.8 are more balanced between fungi and bacteria. Balanced microbial activity contributes to the availability of nitrogen, sulfur, and phosphorus in the soil. Earthworms also like a pH near neutral so their sticky coating does not dry out. Earthworms are natural aerators and help to form soil aggregates, that in turn improve soil structure.
How much & what kind of lime?
Often, not nearly enough lime is put down to either help or hurt the soil. It is critical to soil test with a reputable laboratory for at least pH, buffer pH, calcium and magnesium to determine how much and what kind of lime to use. Buffer pH provides an indication of the soil’s resistance to change, or how much lime will be necessary to cause a change in the soil’s pH. The decision on which lime to use—calcitic or dolomitic—is determined by the calcium to magnesium ratio. Without realizing it, you may be raising the pH while creating an imbalance in the calcium to magnesium ratio which creates other problems (i.e., compaction and greater weed pressure).
There is still time to soil test, and lime can be applied until the ground freezes. PJC is available to help with soil testing, interpreting results, and supplying the right product.