Simply put, a dethatcher is a device that effectively removes thatch from your lawn. A dethatcher can be as simple as a rake, towed behind your tractor, or even motorized for commercial jobs. A dethatcher uses metal blades or tines to comb across the grass and pull thatch up to the surface of the lawn.
Small dethatching blades are sold as lawn-mower attachments, but they're not the best choice because they put a lot of strain on the mower. Most people rent a power dethatcher.
Dethatching helps reduce thatch. A thick layer of thatch can prevent water, air, and nutrients from reaching the soil and roots, making your grass susceptible to disease and pests. Dethatching also allows you to aerate your lawn at the same time, which can improve drainage and help the roots grow deeper.
Dethatching usually involves a riding lawnmower with a unit mounted to the front of it that has spring tines that moderately dig up thatch just ahead of the mower bagging it up.
The best time to dethatch your lawn is when it's actively growing and the soil is moderately moist. For cool-season grasses, that's early spring or early fall. For warm-season grasses, dethatch in late spring through early summer (after the second mowing). That's when your grass is growing most vigorously.
After dethatching, your lawn may look stressed and thin with dry, dead-looking patches. It's normal and part of the process of keeping your lawn healthy. As long as you take proper measures, you should be able to restore your lawn to its lush and green state.
If your lawn has a thick layer of thatch that prevents water from reaching the soil, dethatching is the way to go. However, if the soil is compacted, making it difficult for roots to grow and absorb nutrients, aeration is more beneficial.
Benefits of dethatchers
Dethatching promotes healthier and stronger lawn growth. By leaving some thatch behind, humidity and temperature are stabilised. Airflow around the root system is improved, resulting in better growth. Dethatching results in less shock and damage to the lawn.
A dethatcher uses metal blades or tines to comb across the grass and pull thatch up to the surface of the lawn. After the thatch is pulled to the surface, it can be bagged up or turned into compost.
Measure The Thatch.
Use a trowel or spade to remove a wedge-shaped layer of grass and soil about 3 inches thick, or just pry up a small section of turf. Look for the thatch layer lying directly on top of soil. Measure the thickness. A layer thicker than ½ inch signals it's time for dethatching.
The prongs on a rake do not penetrate deep enough into the soil to be able to remove the thatch. Chances are, a rake would glide right over it! We recommend using a rake to remove loose leaves and debris first, then choosing either a dethatcher or a scarifier to tackle the thicker build-up of material below.
Water from irrigation can accumulate in the thatch layer, too, so grass roots suffocate from lack of air. Thick thatch also provides a breeding ground for lawn disease and insect pests. Some lawn grasses are more prone to thatch buildup than other.
Dethatching in the spring is a bad procedure for several reasons. First, it tears and rips turf that is often still dormant and therefore will be unable to recover after winter injury, snow mold and ice damage. Spring dethatching hits a lawn hard when it is already in a precarious condition.
It also helps to reduce the need for dethatching, which can be a labor-intensive and costly process. Liquid aeration offers a safer and more cost-effective alternative to dethatching. It is much less disruptive to the soil microbial activity, and it can be done quickly and easily.
The best time to dethatch is late summer or early fall. That's when your grass is growing most vigorously. Before dethatching, mow a little shorter than normal. Also, you'll achieve better results if you do it after a light rain or watering.
After dethatching your lawn it is a great time to aerate your lawn. After aerating, overseed and fertilize with Milorganite®. It should take about 3-4 weeks for the lawn to recover and show signs of new growth.
Contrary to popular belief, leaving clippings on the lawn does not contribute to increased thatch.
Remember that you should only dethatch your lawn a maximum of once per year for warm-season grass and between once and twice a year in early spring and autumn for cool-season grass. Warm-season grass should be dethatched in late spring or early summer.
A: A dethatcher will tear out some of the dead crabgrass but won't get it all. The crabgrass will break down and disintegrate over winter anyway. The real problem is the seed these plants let behind to germinate next year.
First, mow your lawn at the lowest setting on your mower. For best results, power rake to remove thatch from the lawn. If you plan on fertilizing your lawn, do so with a broadcast or drop spreader prior to overseeding. It is important not to water prior to seeding.
Identifying Thatch
If thatch is present, it will appear as a distinct layer of stringy or felt-like material (Figure 1) between the soil level and green grass stems. The thatch layer should not exceed 1/3 inch thick in a cool-season grass lawn comprised of fescue, bluegrass or ryegrass.
During extremely hot weather: Aerating during extremely hot weather can also cause additional stress to the grass and make it more susceptible to disease.