Excessive lawn thatch that is allowed to build up and become too thick can cause several issues for your lawn. Problems such as poor drainage, lack of air to the roots, and trapping nutrients in the soil are just a few of the issues you might face if you don’t keep on top of dethatching. But how much thatch is too much thatch, and what should you look out for? Let’s find out.
How Much Thatch is Too Much Thatch? (The Short Answer)
Lawn thatch should not be allowed to build up more than ½ an inch. Once thatch becomes too thick, your lawn will start to show signs it is struggling and begin to die. A thick layer of thatch forms a barrier between the soil and the above-ground environment preventing your lawn from receiving all the necessary elements it needs to live.
How to Measure Thatch Depth (+ Why You Should)
There are a handful of different methods you can use to measure thatch depth on your lawn. These can be as simple as digging down into the soil with your finger or removing a coil of soil using a handheld soil core tool.
Personally, I use a small garden spade or a trowel to pry apart the top few inches of soil. So, all I do is dig my spade or trowel into the soil, push it forward a little, then remove my tool. This method gives me just enough access to the soil to get a good look at the top few inches. Then, once I’ve finished, I just tread over the soil a few times and close up the hole. This method only takes a few seconds to complete and doesn’t leave behind any obvious signs I’ve been digging in my lawn.
Part of the reason I use this method is that I want to get a good look at the layers in the soil without disturbing them. My garden spade cuts through the thatch and soil without mixing them, making it easier to tell how thick the thatch layer actually is. I find that the finger-digging method makes it hard to tell how thick the organic layer is, and removing a soil core is unnecessary.
How to Tell If Your Lawn Needs Dethatching (Watch Out for These Signs)
Other than looking at the thatch layer on your lawn, there are a few signs you can watch out for which don’t require any digging. You can keep an eye out for these signs throughout the year without using a spade.
Grass Turning Yellow
One of the first visual signs you’ll notice if the layer of thatch on your lawn is too thick is that your lawn will begin to lose its green color. The thick layer of thatch blocks nutrients, water, and air from penetrating down to the roots. So, as the roots struggle to get what they need to survive, they enter survival mode and will turn the grass blades a yellowish color, signifying their poor condition.
Lawn Staying Wet for Longer
One thing you’ll notice when you have too much thatch is that the ground will stay wet for longer. This is because the thatch will act like a sponge and soak up a lot of the water from the rain and your irrigation. So, rather than the water soaking into the ground, it will stay soaked up in the thatch.
Grass Turning Brown
Not only might your lawn turn yellow, but it could also turn brown. Brown grass signifies that the thatch is holding onto a lot of the water preventing the grass from getting what it needs. An extra ½ inch of thatch can cause a huge problem when it comes to getting water down to the roots. So, your lawn acts like there is a drought even though plenty of water is available. So, if you see signs that your lawn might be drying out, it would be a good idea to check if it needs dethatching.
You Can See the Thatch in Your Lawn
One of the most obvious signs that your lawn needs to be dethatched is that you can actually see a lot of brown in your lawn. This is where the thatched layer gets so thick that it starts to rise out of the lawn. You should see very little thatch when you look over your lawn. Ideally, thatch composts below the top section of the grass blades and works its way into the soil. So, if you’re noticing the thatch getting taller and taller on the soil bed, then this is a good indication the thatch is becoming too thick.
Lawn Not Responding to Fertilizer
Another sign of how to tell if a lawn needs dethatching is if the fertilizer you’re adding to your lawn isn’t making much of a difference. The thick layer thatch creates a barrier that prevents the fertilizer from penetrating the soil. So, just like the thatch prevents water from entering the soil, it also traps the fertilizer.
Grass Type & Time Elapsed
The last couple of signs to look for when figuring out how to tell if the lawn needs dethatching aren’t really signs at all. They are more like factors that determine when you should be dethatching. Let’s take a look at what these are.
Grass Type
Nearly all grass types like to be detached at some point. Depending on the growth rate, you can use either a power rake or a dethatcher. You’ll find that warm-season grasses like Buffalo, Bermuda, and Zoysia grow quickly, producing many grass clippings that build up a thatch layer very fast.
On the other hand, cool-season grass like Ryegrass, Fescue, and Bluegrass all grow slower, producing fewer clippings that need to compost. But regardless of which season grass type you have, it is nearly always going to need to be dethatched at one time or another.
Time Elapsed
I can look at my lawn care calendar and figure out that I need to dethatch my lawn around April and late October. So, without even looking at my lawn, I know that if I haven’t already dethatched in spring, my lawn thatch will be too thick by May or June.
How to Keep Ahead of Lawn Thatch
If you want to keep ahead of thick lawn thatch, then just follow these six points. This will maintain your thatch at a beneficial thickness and keep your lawn happy and healthy.
Finally, how much thatch is too much thatch? Anything more than ½ an inch.
- Know How Often Your Grass Type Should be Dethatched
- Know When in the Year Your Lawn Should be Dethatched
- Understand How to Measure Thatch Depth
- Keep an Eye on the Grass Color
- Watch How Water & Fertilizer is Absorbed
- Make Sure Thatch Doesn’t Become Visible on Top of Your Lawn
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