Deciding whether or not you should dethatch your lawn each and every spring will depend on several key factors such as your type of grass, how thick your thatch layer is, and what thatch removal equipment (or products) you are planning on using. In this article I hope to explain these factors clearly while providing a healthy dose of supporting and supplemental information that adds to your knowledge base.
Is there another time of year that your lawn would be better suited for dethatching?
Dethatching your lawn in early to mid-Spring is best for most grass types because that’s when grass plant systems put on the most leaf and root growth. The damage physical dethatching does to lawns is temporary and can be quickly repaired naturally when lawns are growing vigorously. Not all grass types need to be dethatched every year though. Usually only rhizomatic and stoloniferous types will benefit from annual dethatching.
The exception to this would be all warm season grass types (St. Augustine, Bahia, Bermuda, etc.) which don’t typically grow their fastest until the end of Spring so dethaching down south should be delayed until May or June unless you plan on only dethatching with liquid sprayable products.
Make sure to see this post for a description of how these sprayable products work and which liquid thatch remover is best.
Keep In Mind Why We Dethatch In The First Place
Dethatching is an excellent option for all lawns, no matter the grass type, to stay in the best condition possible. Dethatching helps maintain the rich green color that that we all want in our turf grass by removing the dead brown material that builds up over time.
Thatch removal also aids in the reduction of undesirable insects or pests living in the grass and it will ensure that your irrigation during the dry summer months or fertilizers you apply throughout the year actually reaching the soil surface and the root systems below.
Physically removing thatch with an electric dethatcher or thatch rake can cause more harm than good when done at the wrong time of the year. The upper most layer of organic matter that accumulates on the surface of a lawn gets matted together with healthy roots so removing it during periods of plant stress can make it hard for healthy grass to recover.
For physical thatch management it’s best to wait until the layer is at least 1/2″ thick before aggressively scarifying the lawn. Routine liquid thatch management programs however are best for maintaining healthy levels of thatch in the lawn from mid-spring through mid-fall for any grass type with thatch greater than a quarter inch thick or more.
If I had to answer whether you should dethatch your lawn every spring (sight unseen) I would recommend that you do not dethatch at that time of year every year unless you knew you had a problem. I would also advise applying liquid thatch management products annually to nearly all grass types throughout the warmer months of the year to help prevent thatch buildup.
Make sure to see the following posts for specific tips on thatch removal:
Now as for getting the job done before spring near the end of winter I want you to see the following video I produced not long ago.
What is Thatch Anyway & What Does It Do
Thatch is that part of the turf that consists of old and dead roots. It is that layer that separates the turf from the soil surface.
Thatch build-up does not result due to grass clippings. In fact, grass clippings actually help to reduce thatch problems by decomposing rhizomes and old grass roots.
A thin layer of thatch (½ inches or less than that) isn’t harmful; in fact, it is advantageous for the plants. A healthy thatch range helps to prevent fluctuations in soil temperature. It also helps to make sure the soil doesn’t lose excess moisture.
Though, if this layer keeps building up over time, it might lead to a thatch problem. A thatch layer of 1/2″ or more can start posing a threat to the health of your lawn. This is because, it might pose an issue in allowing nutrients, water, and air to penetrate into the soil. You can usually feel the thickness of your thatch by how squishy the lawn feels but a spongy lawn doesn’t always mean you have thatch either.
Here Are The Main Benefits Of Dethatching A Lawn In The Spring
- Removes dead matter from the yard so a spring lawn can green up faster. This is often dead and matted grass and/or leaves, the remnants from the prior fall and winter seasons. This material begins to break down on the surface and acts as a mulch which can be good up to a certain point and then detrimental once it becomes too thick.
- As the thatch thickens, it can become a serious moisture barrier. This will act as a very dry sponge during the driest summer months when you need to be irrigating the most. When you water the lawn all of the water will get soaked up into the thatch and not reach the soil and the roots of the grass. This means you end up having more dead grass or have to use up a lot more water than you otherwise would need.
- It can impede the exchange of oxygen flow into the topsoil causing an anaerobic environment which is detrimental to your soil biology and nutrient usage. In order to maintain a healthy lawn the soil needs to be able to breathe. This is why people will aerate a lawn…but don’t get confused, aerating a lawn is not the same as dethatching and they should not be done at the same time.
- Dethatching in early Spring opens up pathways for nutrients to reach your soil surface more reliably when you fertilize. Applying products of any kind to a lawn with a thick thatch layer is not efficient. Many products will take too long to penetrate the thatch layer ad get to the soil. When lawn products are not in the soil then many of them will oxidize much quicker than normal and won’t have the desired effect on the lawn.
With that summary out of the way let’s look at what grass types need annual thatch management and discuss the reasons why the other grass types may need occasional remediation.
The 3 Most Obvious Signs Your Lawn Needs To Be Dethatched
- You lawn is spongy and is difficult to push a lawn mower through the lawn.
- Color variations from green to brown are visible in the lawn.
- When you peel a layer of your lawn back or pull a core out of it the thatch layer is thicker than ½ inch
Even if you run a bunch type grass that doesn’t normally develop thick thatch layers these are good points to keep in mind.
For the warm season grasses and cold season grass types that spread via rhizomes and stolons however annual thatch management should be regimented.
Your Grass Type Usually Dictates When You Need To Dethatch
Cool Season Grass Dethatching
If your home is in a location with cool season grasses like Kentucky bluegrass, Creeping Red Fescue, or Creeping Bentgrass then the early spring or late summer is the ideal time to dethatch because these grass types will be going into high growth mode at those times.
Warm Season Grass Dethatching
If your turf grass is made up of warm season grasses such as Bermuda grass, St. Augustine, Centipede, or Zoysia then you should plan your dethatching efforts after the late-spring green-up phase, just before these grasses enter the early summer season, which is when their growth is at their peak.
Plan to dethatch prior to best growing season for your grass. It is ideal if the grass will have at least a month and a half of peak growing season left after dethatching to recover from the damage caused by physical thatch removal.
You never want to be dethatching when your lawn is dormant or stressed from the weather as it possible to damage it severely and take a year or more to recover.
If you plan on applying liquid thatch removal products then the timing changes considerably for all grass types. I recommend see this post on how liquid thatch removal products work for best practices.
Top Reasons For Not Dethatching In The Spring
- The biggest reason to not dethatch in the spring (and certainly not in the early spring) is that it tears up the turf when the grass is still dormant or just coming out of dormancy. This is why it’s not advised to dethatch every year unless your lawn actually has too much of it.
- It is very disruptive to the top layer of soil and can encourage the growth of weeds when weed seeds are sometimes brought to the surface making it easier for them to germinate. If you have crabgrass issues the last thing you want to do is disturb the soil prior to its germination.
- Some cool season grasses can be slow to grow in disturbed areas that were dethatched too early leaving you with bare spots in your yard.
Thatch build-up varies with turf type, but even still, dethatching shouldn’t be a regular lawn care exercise. Unless it is absolutely necessary to, don’t physically dethatch often, instead mange what you have with liquids.
Thatch takes time to build up, and so dethatching every spring might be unnecessary and, worse still, harmful to your lawn. Because it is unlikely that if you do everything right, you’ll have excessive build-up in a period of one year.
Consider dethatching every couple years if you’re growing warm-season turfs and every few years if you’re growing cold season turfs but always look at your conditions first, you may not ever have to dethatch if the layer doesn’t ever get too thick.
Do not dethatch regularly, except when you see the need to. You should inspect your lawn’s thatch thickness on an annual basis. If it is thicker than ½ an inch then let your grass type guide your next move. A cool season or warm season turf grass will dictate if you should dethatch your lawn in the early spring or late spring. In doing this, your lawn will have enough time to recover, without risking the chances of being severely damaged beyond repairs.
For more tips on thatch make sure to see the follow resources here on the site: