Insects, disease and weeds thrive on barren soil. Fungus infections, chinch bugs and other pests attack shallow-rooted grass. Roots struggle to penetrate the compacted soil. They become weak and thin. The beneficial organisms which help process nutrients for the turf and decompose organic material cannot survive in such an environment.
Instead of growing lushly, turf will focus energy on simply surviving. Without moisture, air flow and organisms, it eventually loses the battle. Then the homeowner is forced to resod.
The best practice to combat compacted soil is to aerate followed by a top dressing of organic matter. This allows oxygen, nutrients, micro-organisms and moisture to penetrate the soil. Aeration involves removing plugs of soil at intervals. Top dressing with organic matter (compost) and water or rake it in. This will help the compost to filter down into the holes.
How to aerate
It’s much better to remove the plugs of soil than to simply spike the soil. Spiking simply compacts the sides of the holes. Aerators come in different configurations. Several are simply hand tools resembling garden forks. However, instead of solid tines, they have small cylinders which remove plugs of soil. Some come with hose attachments. These add water to the hole at the same time they are taking plugs out. There are push aerators, which resemble reel lawnmowers, and larger ones with gasoline engines that power themselves. There are also professional landscaping companies which have large industrial aerators. Some outlets rent aerators.
Organic matter and fertilizer
After aeration, add organic matter. Simply spread ½ inch of compost over the turf and either rake or water it in. A 1,000 square-foot lawn needs about 1.5 cubic yards of compost.
Fertilize lightly. Too much fertilizer, or fertilizer with too much nitrogen, can actually harm turf grass by attracting insects that feed on the grass, or damaging the lawn with high levels of mineral salts It will also cause a high flush of growth that can lead to fungal diseases.
Weed and feed products also stresses turf, especially St. Augustine. These can also damage tree roots. It’s also a waste of money. Herbicides need to be applied in late winter, while fertilizer should be applied in late spring. Using them both at the same time wastes one or the other.