Thatch occurs naturally in most lawns and is generally not bad. However, there are times when thatch can build up and cause lawn problems.
What is Lawn Thatch?
The grass in lawns grows, matures and the old grass dies off in a cycle. So what is tha definition of a lawn thatch? Well it is the dead grass debris which lies between the live grass blades and composts naturally at around the same rate as it is replaced by new growth.
What does thatch mean for your lawn? An element of thatch is always present in lawns and it is a good thing.
Approximately ½” of thatch in a lawn is about right.
What is Thatch Grass?
Thatch is a natural component of lawns. It provides insulation against temperature fluctuations that may damage new growth.
Thatch on a typical home lawn provides a soft spongy feel underfoot. In a similar way, thatch on sports pitches is also good as it provides a cushion against impact on the ground.
In some lawns the thatch layer becomes too thick and begins to cause problems for your lawn.
Fertilizer is the Principal Cause of Excess Thatch
Some types of grass are more prone to excessive thatch than others. Most domestic lawns use ryegrass and / or fescue, which do not produce thatch quickly.
Sports pitches often need to recover quickly from use. Growth on such surfaces is encouraged with the use of fertilizers, which in turn create new growth faster than the lawn is able to absorb dead grass, resulting thatch. As noted above, higher levels of thatch on sports pitches is often tolerated due to its cushioning ability.
In the same vein, the principal cause of excess thatch build up in most domestic lawns is the use of excess fertilizer.
Excess nitrogen in fertilizer can promote rapid new growth in lawns. This rapid growth means that the lawn is unable to compost the dead grass fast enough, resulting in a build-up of thatch.
There are other causes, such as the use of some pesticides, the soil acidity and, as already noted, the type of grass being grown. However, in most domestic conditions, excess fertilizer is the culprit.
One of the best ways to dethatch your lawn is not to allow it to grow in the first place, so take care when choosing and using your lawn fertilizer.
What is Dethatching a Lawn?
Thatching, or dethatching your lawn is the process of removing thatch from your lawn. Since we have established that thatch is essentially dead grass lying among the blades of grass in your lawn, dethatching your lawn requires using a dethatching tool to remove dead grass.
There are a number of dethatching tools to choose from, but they essentially fall into one of two categories, the manual dethatcher rake, or the power rake.
What Does a Dethatcher Do?
A dethatcher is a rake that lifts and pulls out the dead grass from the remaining live grass blades.
A manual thatcher rake, sometimes called an aerator rake or dethatching rake are sharp bladed rakes that cut through the dead grass layer lying at root level allowing it to be pulled out. It is literally a process of raking out dead grass from your lawn.
These tools are different from conventional garden rakes. The tines of a thatcher rake are sharp allowing them to slice through the matt of dead grass. They are also quite robustly built as the process of removing thatch is hard work.
Because it is hard work, power rakes were developed. A power rake is very simply a tatcher rake with a motor. Power rakes make the process of dethatching your lawn a great deal easier. You simply set the height you want the tines to cut and off you go.
When to Dethatch Your Lawn
Excessive thatch growth however can cause problems and needs to be removed.
Thick thatch spoils the rich green appearance of a lawn making it appear brown and sun burnt. Too much thatch can retain heat causing damage to new growth. In a related way, thatch can hold too much water in wet conditions, which reduces oxygen access to new grass.
How Do You Know When to Dethatch Your Lawn?
When you have dethatched a lawn you want need to give the lawn grass time to recover. Your lawn may well look terrible. It can take a couple of weeks for the lawn to return to health and you may wish to seed the lawn to encourage growing in any bare patches that have resulted. So, if you want to know when is the best time to dethatch your lawn, you really need to consider when the best growing period is and time your work to be just ahead of this.
The two best growing seasons for your lawn are spring and fall. As a result, the best time to dethatch your lawn is also spring and fall. Some grasses, cool season grasses, grow best in fall and if you have such grass in your lawn, then fall is preferable to spring.
We’ve established what is thatch grass, we’ve established what is dethatching a lawn and what a dethatcher does, and finally we’ve established when is the best time to dethatch your lawn. Now, let’s move onto how to dethatch your lawn.
How to Dethatch a Lawn
For small areas, we recommend a thatcher rake. The sharp-tined thatching rake is designed to cut through and rip out the thatch from the base of your lawn.
Work systematically so you know exactly where you have raked. Dig deep so that the blades penetrate the thatch to break it up and loosen it. Remember we want to time our work so that it doesn’t affect new grass shoots. Once complete remove the dead grass, do not leave it lying on the lawn as it will simply settle back and reform.
Larger Areas or Whole Lawns
If you have a larger area to deal with we would recommend a power raker. Power rakers can be rented relatively easily from garden centers or equipment rental outlets or you can buy your own.
Again, be systematic. You first need to establish the blade depth. You want the blades to cut the thatch, but not penetrate the live grass roots. Test, the power raker on a small patch of lawn that is out of sight of the main lawn. You may need trial and error to establish exactly the right height.
Power rakers are very effective. You will only need one pass. You will be surprised at how much thatch is removed from most lawns. Unless your lawn has excess weeds the thatch is good for composting and will form part of the brown waste element of your compost.
Lawn Dethatching Tips
- Work in a systematic way to avoid unnecessary damage to the lawn.
- It is worth making a note of the height setting to save yourself time the next time you decide to dethatch your lawn.
- Be aware that dethatching makes your lawn look pretty awful afterwards. This is perfectly normal. Dethatching is a positive step to return your lawn to full health, but the process is not without some temporary impact on your lawns appearance.
- Immediately after dethatching water your lawn well and avoid unnecessary traffic until it has begun to recover.
- Following dethatching it is also a good time to aerate your lawn and overseed to encourage fresh growth.