The What? Why? And How of Thatch?
It’s not just the straw roof covering the tropical cabana, of which I’m currently dreaming as I endure the Colorado cold! Thatch is also known as the accumulation of grass clippings, roots, and other debris after several seasons of mowing a lawn. Short term, this is usually a welcome occurrence. It can be very beneficial in moderation and likened to our skin. A thin layer can help protect the lawn from disease, drought, and dramatic weather swings. However, it can be harmful in excess. If unchecked, thatch can deprive grass of the nutrients and oxygen it requires to be healthy and happy.
How Much Thatch?
How much is too much? Well, seeing for yourself is probably the best way to learn! Grab a shovel, dig about 6 inches deep, and remove a piece of grass. The organic layer between the brown soil and the green grass is thatch.
A thin layer – less than an inch – is ideal, as it acts like a natural layer of mulch. This helps with water run-off and protects the root of the plant. But once the layer is above an inch, the opposite can happen. Watering a lawn with thick thatch blocks the plant roots from receiving the water, air, and nutrients necessary to thrive. Essentially, it absorbs all the water and turns into a wet blanket. In turn, the roots suffocate, inviting fungus and disease. Worst-case scenario: it becomes so thick that the plant’s roots cannot penetrate the soil and are forced to grow in the layer of thatch. The result? Thin and sickly-looking turf.
Why Do Lawns Develop Thatch?
There are a couple of main reasons why lawns develop thatch. The first and most obvious is not raking the debris from clippings and falling leaves. This organic material will continue to stack over a few seasons and eventually snuff out the roots. A second reason is compaction. Compacted soil doesn’t allow water, air, and nutrients to penetrate the root zone of your grass.
Soil conditions are a common problem along Colorado’s front range due to ribbons of compacted clay loam. Clay soil has a poor pH balance which prohibits microbes from breaking down the organics. Without amending the soil with organics and nutrients, this condition makes growing healthy plants difficult.
The Solution?
So, what do you do if your lawn is looking thin and unhealthy? Spoiler alert, the answer is in the title. Yes, that’s right, we need to dethatch! Just as it sounds, dethatching is the process of removing that pesky layer of thick thatch. In fact, dethatching is an important part of lawn care and recommended every 3 years or so.
There are a few ways to dethatch. If your lawn is healthy, the best way is using a hand rake while working up a sweat.
However, there are several tools designed to remove thatch.
- Manual dethatching rakes:
- Effective for relatively thin thatch and small lawns.
- A dethatching rake is heavy, with short tines and curved blades that sink into and pull up the layer of thatch.
- Power dethatching rakes:
- Similar to a mower.
- Feature rotating tines similar to those on a manual rake.
- Effective on thin to moderate thatch and only on lawns that can withstand intense raking.
- Vertical mowers:
- Suitable for thick thatch on lawns needing significant renovation.
- Also called a verti-cutter.
- Have vertical rotating blades that dig into the soil and pull up the thatch.
- Provide adjustable blades so you can choose how much thatch to dig up with each pass.
If dethatching is long overdue, it can be too much for these tools to remove. In this case, the best solution is to remove the turf and start from scratch with new sod. This is costly and best to avoid.
Also important to note: dethatching is a stressful event that also removes healthy grass. As such, overseeding and fertilizing a lawn is always recommended to support resilience. In accordance, the best time to dethatch is early spring, around the same time aerations are performed.
Moving Forward
When your lawn returns to a healthy layer of thatch, there are a few ways to maintain optimal health:
- Proper aeration.
- Avoid mowing the turf too short.
- Rake most of the leaves/clippings in the fall.
These best practices will ensure that you enjoy a beautiful, green, healthy lawn!
If you need a professional to de-thatch your commercial lawn, please contact us. We are happy to help!
For more information on de-thatching, you can visit:
1520 – Thatch – PlantTalk Colorado