Slit seeding is done by using a machine with steel blades that spin at a high rpm and slice through the turf and into the soil. The narrow slits are approximately ½” deep and as the seeder moves forward, the seed is dropped into these narrow slits.
Best results occur when you run the machine in two different directions at a 90 degree angle to your first pass. By applying half the amount of seed on each, you ensure that the entire area has been addressed and has received the correct amount of seed. Slit seeding is usually done when a complete renovation is needed, or when addressing thin or bare dirt areas.
Core aeration is the process of pulling plugs of soil and depositing them on top of the grass. The cores are approximately ½” in diameter and approximately 3” in length. This creates thousands of small pockets throughout that will catch and hold air, nutrients and water. It will also help in stimulating root development.
Core aeration can help reduce moderate compaction issues. Heavily compacted clay soils such as new construction, should have compost and other amendments added in at the time of aerating. Core aeration will help lawns with thatch levels of no more than 3/4″. Lawns with thatch levels above that or more need to have a complete renovation done.