It’s Time to Dethatch and Aerate! – Craig' Sales-Service-Rental

Aeration, Dethating and Overseeding

WHAT IS AERATION?

Technically speaking, aeration is the naturally occurring process of air exchange between the soil and its surrounding atmosphere. Practically speaking, aeration is the process of mechanically removing small plugs of thatch and soil from the lawn to improve natural soil aeration. It’s commonly called “core aeration” in the lawn service industry, and you may have heard of it as soil cultivation (coring, spiking and slicing). Most homeowners simply call it aeration.

WHY IS AERATION NECESSARY?

Compact soil prevents grass from establishing a healthy root system and keeps water and fertilizer from reaching the roots.

In most home lawns, fertile topsoil may have been removed or buried during excavation of the basement or footings, forcing grass to grow in subsoil that is more compact, higher in clay content and less likely to sustain a healthy lawn.

Walking, playing and mowing will compact soil and stress lawns. Raindrops and irrigation further compact the soil, reducing large air spaces where roots readily grow. Compaction is greater on heavy clay soils than on sandy soils, and it is greatest in the upper 1 to 1 1/2 inches of soil.

Aeration can help relieve soil compaction, allowing your grass to grow deeper roots and make better use of water and fertilizer.

WHEN IS THE BEST TIME TO AERATE?

If you have cool season turfgrass such as Kentucky bluegrass and perennial ryegrass, both spring and fall are ideal times to aerate. In spring, aerate between March and May. Perform fall aeration between August and November. Aeration before or at the time of late season fertilization enhances root growth and improves spring greenup and growth.

Warm season turfgrasses such as zoysiagrass and bermudagrass should be aerated in mid-spring to summer. Avoid aerating when warm season grasses are dormant – it may encourage weed competition. In addition, avoid aerating warm season grasses during spring greenup, and not until after their first spring mowing.

Why Dethatch?

Thatch can keep water and air from reaching the soil and, if left untreated, can create an environment that harbors pests and diseases. Dethatching removes those layers of dead grass, roots and debris matted between the soil and the growing grass, keeping the grass greener and healthier while minimizing the chance of disease.

WHEN TO DETHATCH A LAWN

Depending on where you live in the country, and if you have cool-season grass or warm-season grass, you should dethatch in early fall before you fertilize, or in the spring after the grass has begun to green.

If you are planning to overseed a lawn, you should plan to dethatch before seeding.

WHAT IS OVERSEEDING?

Overseeding is the planting of grass seed directly into existing turf, without tearing up the turf, or the soil. It’s an easy way to fill in bare spots, improve the density of turf, establish improved grass varieties and enhance your lawn’s color.

If a lawn looks old, or just “worn out,” if it needs growing amounts of water and fertilizer to thrive, or is disease or insect prone, it’s a perfect candidate for overseeding.

THE BENEFITS OF OVERSEEDING

Many older lawns were established with common type turf grasses not suited for the needs of today’s homeowner. They’re often more disease and insect prone, requiring more fertilizer and water.

Overseeding newer turfgrass varieties into an older lawn can help it better withstand insects, disease, drought, shady conditions and heavy traffic. The investment in overseeding pays off by reducing the amount of fertilizer, water and pesticides required. Most importantly, a renovated lawn stays greener and looks thicker and healthier!

BEFORE YOU OVERSEED

For various reasons, old turf sometimes deteriorates dramatically or dies out completely. Overseeding with an improved grass seed mixture can get new turf growing in bare areas as well as “sprucing up” areas where the turf is thin and unhealthy looking.

First, however, you must analyze the problems that caused the original turf to deteriorate. It might be due to conditions that, if not corrected, will eventually cause the overseeded lawn to deteriorate, too.

Correctable problems include:

Poor soil condition
Improper drainage
Soil compaction
Insufficient water
Poor fertility
Poor air circulation
Insufficient sunlight
Excess thatch
Grass varieties not suitable for the area
General neglect

If you have trouble identifying the problem, ask your local lawn professionals or your county extension office. The main thing is to correct the problem before you establish new grass.

WHAT ABOUT CARE AFTER OVERSEEDING?

Depending on conditions and type of seed, new grass seed will begin to emerge in 5-7 days after seeding when moisture and soil temperatures are adequate. An overseeded lawn can be fully established in eight weeks or less.

Proper watering is critical to successful overseeding. The following is a recommended watering program.

Immediately after overseeding: Water heavily to wash grass seeds into slits.
Until grass seeds germinate (first 10-14 days): Water lightly on a daily basis, soaking first one inch of soil.
After germination: Water less frequently, but allow for deeper soaking and penetration into soil. This encourages deeper root growth.
After grass becomes established: Water at the recommended level for the type of grass planted.

The key is care and patience. Proper overseeding will produce a healthier, better-looking lawn that responds better to mowing, fertilizing and watering. An added benefit is increased property value!

RECOMMENDED STEPS FOR COMPLETE RENOVATION

Use a weed killer and the manufacturers instructions.
Use a power rake to dethatch and remove excess (1/2 inch or more) thatch debris from the treated lawn.
Aerate thoroughly, using a core-type aerator.
Fertilize with a good starter fertilizer. Apply at the recommended rate.
Re-seed, using a mechanical “slit seeder.”

Tip: Reduce the recommended seeding rate by one-half and cover the area twice, in two directions, leaving a “cross-hatch” seeded pattern at a 45º angle.