Every lawn can benefit from aeration (core cultivation) and it will help reduce thatch and soil compaction. If the aeration is done well, once in the spring (March-May) and once in the fall (September-October) will probably be sufficient. A good core cultivation job entails actually pulling plugs of soil out of the lawn. Avoid solid-tine aerating equipment that just pokes holes in the soil surface and can actually increase compaction between the holes. With core aeration, the plug holes should be 2 to 3 inches apart in all directions, and 2 to 3 inches deep. Depending on the quality of the equipment used for aeration, it may require going over the lawn 2 to 4 times, although very good aeration equipment can do the job with one pass. It often helps to water the lawn (with 1/2 to 3/4 inch of water) 1 to 2 days before core cultivation is attempted. The soil should be moist, but not soggy. Again, it is important that the plugs of soil be pulled up and left on the lawn surface. If the lawn is too wet, you will only make holes. If it is too dry, the aerator tines will not penetrate into the soil. The soil plugs can be left on the lawn; they will break down with irrigation, rain and mowing. There are many companies that can be contracted to perform core cultivation for a fee. You can also rent equipment to do your own aeration, but you may not be able to do as good a job as the contracted companies can because of rental-equipment limitations. Aeration is also a great method to prepare for overseeding a thin lawn. Broadcast seed throughout the aerated area and water daily, keeping the soil surface moist, until the seed has germinated. A starter fertilizer can also be applied to get the new turfgrass off to a good start. Begin mowing the new turf as soon as it reaches an appropriate height. Be sure to use a sharp mower blade to prevent pulling the new seedlings out of the ground. Finally, weed control can be addressed once the new turfgrass has become established and has been mowed three times.
