Revive Your Fescue Lawn With Core Aeration & Overseeding

With the vast heat we have been experiencing this summer, it is hard to imagine, but fall is right around the corner and now is the time to start thinking about preparing your fescue lawn for next year by having your lawn core aerated, fertilized and overseeded. Mother Nature has been extremely hard on fescue lawn this summer due to the excessive heat of the day plus the high humidity at night. The heat dries out the lawn causing drought/heat stress while the humidity brings on nasty funguses. Both of these factors are extremely detrimental to your lawn’s appearance, texture and overall health. To aid in the lawn’s recovery and appearance, turf experts recommend that every year in the fall, fescue lawns need to be core aerated, fertilized and overseeded in order to have a beautiful plush yard in the spring.

Core Aeration Process

Especially critical in Georgia’s clay soil, core aeration is performed on turf areas as a means of reducing soil compaction, reducing thatch, and improving the infiltration of water, air, and nutrients into the soil. When soil is less compacted, grass is able to grow deeper roots. Greater root-depth is crucial to helping your lawn survive periods of drought and stress. Greater nutrient absorption means you will have greener, thicker grass to outcompete weeds. When overseeding, core aeration vastly improves seed-to-ground contact versus plain overseeding alone.

The process of aeration is performed by a machine called an aerator. A core aeration machine may look similar to a walk behind lawn mower, but it is much heavier and much more difficult to maneuver. A core aerator has dozens of hollow tines on a roller or drum. When pushed across your lawn, the weight of the machine pushes these tines into the ground and removes thousands of plugs 1-3 inches in length, loosening the soil. Even more effective, some companies perform aerations with a pneumatic aerator, where they can apply higher pressure on the roller or drum by hydraulic pressures up to 300 psi, allowing the tines to penetrate even deeper into the soil.

What Kinds of Grass Need Overseeding?

Not every grass type requires overseeding. The practice of overseeding lawns is primarily reserved for cool season bunch-type grasses such as tall fescue, fine fescue, perennial and annual ryegrass and occasionally bluegrass. There are exceptions, but for most home lawns, warm season grass types that spread by the production of “runners” are not generally overseeded. Most cool-season grasses are bunch-type grasses. As the name sounds, they grow in a bunch, but growth habits are largely misunderstood. When lawn grass seed germinates, a single grass blade emerges. The grass crown (at the plant’s center) have roots growing down from the crown and the blades growing up. Grass plants expand as new grass blades, called tillers, develop and grow alongside the original crown. Hundreds of new tillers can develop, each having its own crown, roots and blades. A blade of grass has a short lifespan of about 6 weeks and must continually produce new tillers or the grass thins out.

Why is Overseeding Lawns Necessary?

After several years, mature plants begin to slow down their reproduction rate. Since a blade of grass lives only an average of 45 to 60 days, production of new tillers must continually outpace the dieback of older leaves. Young grass will produce tillers faster than older grass. Therefore, one of the most important secrets to maintaining a healthy, thick lawn is to make sure your grass is young. The practice of overseeding lawns is the easiest way of keeping grass young.

When is the Best Time to Overseed?

Late summer or early fall. There are many reasons for this. With fall germination, the young grass will have two or three months to become better established before temperatures drop too low and growth stops. Next spring, the young plants will have another few months to develop deeper roots before the summer heat sets in. This is the primary reason, but there are also other reasons for overseeding lawns in the fall. Below are a few:

• Overseeding lawns in fall reduces or eliminates competition from summer weedy grasses, such as crabgrass, foxtails, and other weeds.
• Soil temperatures are still warm in the fall, which is necessary for seed germination, while the cooler air temperatures are better for grass growth.
• Rain amounts and soil moisture is generally better in the fall.
• Overseeding lawns in the fall gives the grass a head start. The roots have become established before winter, which greatly reduces crop loss should you have a hot, dry spring.

Do You Need Fertilization When Overseeding?

When overseeding lawns, you may find it necessary to apply a starter fertilizer before or directly after seeding. This is especially true if a soil test says your soil Phosphorus (P) is low. Starter fertilizers will contain higher amounts of phosphorus (Middle number on the bag of fertilizer). The reason for the increase is because phosphorus is relatively immovable in the soil. The soil may contain plenty of phosphorus already, but since it doesn’t move or leach, it may not be where the tiny roots can reach it. The only drawback to adding (P) is that weed seeds will benefit from the added phosphorus as well. However, when you remember that a thick turf is your best defense against weeds, added phosphorus will only help you achieve your goals. To learn more about overseeding, take a look at this research by Dr. Clint Waltz at the University of Georgia.