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:
Dethatching should only be done if your lawn has a solid layer of thatch on it (at least half an inch). It is usually done either in spring or fall. The process of dethatching puts a high level of stress on the grass, so it is usually done before or after the growing season of the grass. If done in the spring it is important to wait until the snow has all melted and the ground has dried. If you dethatch while the ground is still frozen you will most likely pull up grass that is not just dead, but alive too. If you dethatch in the spring when the yard is wet, you will most likely tear up the soil. If done in the fall, it is important that it is done before the ground freezes for the same reason that you shouldn't dethatch in the spring if the ground is still frozen.
How to Dethatch:
Dethatching can either be done by hand or with a machine. If done by hand, you will use a dethatching rake that is designed to grab the dead grass while mostly leaving the alive grass. You will use the rake to remove thatch from high-thatch areas. Work at the grass from different angles, but do not spend too much time in one section of the yard or you will damage the soil and the live grass. A typical five-thousand square foot lawn can take anywhere from two to four hours to dethatch by hand, depending on the level of detail you observe. The second option is to dethatch with a power rake. A power rake is a machine that uses small wire bristles to remove the thatch. Some newer machines may use plastic instead. A power rake can cost up to $1,800 to buy new but can be rented for around $50-$75 an hour, or $200-$400 a day, depending on where you rent it from. Lastly, whether dethatching by hand or with a power rake, make sure to water the area where you dethatched.Common Dethatching Mistakes:
There are a few common mistakes I have observed homeowners make when dethatching their own yard. The first is that they do it when it is not necessary. You should definitely not dethatch your yard if there is less than a half-inch of thatch on it. However, because of the stress it puts on the grass, I usually wait until there is one inch of thatch on the lawn before I recommend getting it dethatched. The second is that people do not water the grass after dethatching. Just as you should water a plant after transplanting it, you should water grass after dethatching it for the same reason: to help the plant recover from the stress. The last common mistake I have seen homeowners make is the regularity that they dethatch their lawn. Unlike aeration, dethatching is not something that should be done annually. As I said earlier, you should wait until there is about half an inch or an inch of thatch on the lawn. This shouldn't happen yearly, but usually every other year, or even once every three years.
Hire a Professional or Do It Myself?
Dethatching is one of the services that I recommend leaving for professionals. Just as with aerations, there are many mistakes that can be made when performing the service. A professional has many hours of experience doing the job and is less likely to damage the lawn. If you end up doing it yourself, (though I do not recommend it), I suggest that you do it by hand, not with a power rake. Other than the fact that a power rake is very expensive to rent or buy, it is a lot easier to make a mistake with a machine that you are unfamiliar with than it is for you to make a mistake using a rake.
How Much Does it Cost to Get My Yard Dethatched?
Each company charges a different amount for dethatching based on their business's expenses. Most companies will use a power rake and charge one flat fee, but companies that offer hand dethatching will most likely charge by the hour. Dethatching prices are based on many different factors such as yard size, obstacles, inlcine, thatch depth, and grass health. Because of this, each yard will have a significantly different price from another. It is not uncommon for a company in Minnesota to charge anywhere from $100 to $400 for dethatching. Dethatching by hand can cost anywhere from $50 to $120 per man-hour.