By Gene Sumi Homestead Education Coordinator
If you want to successfully grow any plant, but turfgrasses in particular, you must have soil that is loose, which means it is filled with openings between the soil particles - openings that can hold water and air. It's the soil's ability to hold water and air that means life and death to your lawn. The clay will naturally want to come together and form this compaction. You need organic matter mixed in the soil to keep the clay particles apart. The long, hot summer this year has baked the clay soils of our region and those soils that have little or no organic matter are the ones that have turned into one big clay brick. I have advised many homeowners to prepare the soil before planting a seed or sod lawn by mixing in organic material, particularly composts such as Leaf-gro® or Compro®, into the soil in adequate amounts. Many, I am sure, do not do this and are paying the price each year is lawns that fail over and over again.
How to Remedy your Compaction Problem
If you have one of these lawns, you have the choice of two ways to greatly improve your lawns. You can start over and dig up the lawn area and reseed or resod, being sure this time to add organic material, mixing it with the existing soil to a depth of at least 4 inches deep. I recommend using a ratio of organic matter to soil of 1 part organic matter to 3 parts existing soil. This means spreading about 1½ inches of compost on top the soil and tilling it into the soil to a depth of 4 inches. This process will aerate your soil and mix in the material that will help to keep it aerated.
Your second choice, if you do not want to redo your entire lawn, is to mechanically aerate your lawn with a core aerator. This device will cut cylindrical cores (1/2 inch across and 4 inches deep) out of your soil at 4-inch intervals. Core aeration means removing those cores of soil, not just punching holes in the soil using a solid spike device (And about those hole-punchers? Save your money.) The openings left by the removal of the cores will relieve the compaction and open the soil to air, water and fertilizer down to the deepest roots. Follow the aeration with an overdressing of compost, which will filter down into the holes and add needed organic matter. You can rent a power drum core aerator machine at most equipment rental businesses. If you have heavy soil, you should do this mechanical aeration every fall.
Make soil aeration a part of your yearly lawn maintenance program, along with watering, fertilizing, mowing, and pest control.