Aeration and Over-Seeding

I have had great success aerating and over-seeding lawns for many years. This works best in lawns where thickening the lawn or wanting to add new, better, and improved grass varieties is desired. It can also do a fair to good job in filling bare or damaged areas depending on several factors, including soil type, amount of loose soil, amount of seed used and properly watering after seeding. For these types of areas, we usually recommend going over the area two to three times with the aerator and seed. This creates more loose soil and applies more seed.

We use half the recommended seed rate for a new lawn recommendation when over-seeding. If a new lawn rate for a seed mix is 5lbs per 1,000 sq ft, we use 2.5lbs per 1,000 sq ft when over-seeding. This is a very good amount of seed for an over-seeding project. As mentioned above for damaged areas, going over it twice is equivalent to applying a seed rate that would be recommended for a new lawn or bare installation.

Aeration and over-seeding can be done in the spring or fall. Fall seeding is almost always the best choice. Fall aeration and seeding done in the fall provides cooler air temperatures and cooler soil temperatures primarily because evening, night and morning temps are decreasing. We often will begin to have more rainfall in the fall, and morning dew may be significant enough that it could be considered a morning watering.

The absolute most important thing that can be done for any seeding project is water. The goal should be to ensure that the top 1/4” of soil stays moist for a minimum of three weeks. The amount of watering necessary to achieve this is dependent on multiple factors including amount of current rainfall, receiving good morning dew, daily air temperatures, amount of daily sun/cloud cover, shade received through the day, and any type of soil cover such as the current grass stand holding in moisture or using compost or straw to hold in moisture to the soil.

Retaining soil moisture becomes much more critical in open, bare or damaged areas because there is no surrounding grass to preserve soil moisture. In areas such as these, it is recommended to water 2-3 times a day to keep the soil moist. If a good morning dew is received, you may be able to get away with only two additional waterings.

As a final thought, I’d like to add that seed can sit on dry ground and be fine. It can sit for several weeks with no watering. Once it begins to receive water by rain, dew or watering sufficiently enough, the seed will begin to germinate. This is the most critical time! Once a seed begins germination, it must have enough moisture to germinate and grow a root and blade or it will die. This is the point of no return; if it dies, the seed will be done. This is in contrast to what is mentioned above, to a seed that sits dry and does not start germinating.