Thatch gets a bad reputation, but a little bit is actually normal and even beneficial — it cushions the soil and helps retain moisture. The problem is when it builds up faster than it breaks down, which is a common issue with a couple of grass types we sell.
What Thatch Actually Is
Thatch is the layer of living and dead stems, roots, and organic debris that sits between the green grass blades and the soil surface. It’s not the same as grass clippings sitting on top after mowing — those break down quickly on their own and don’t need to be raked up. Thatch builds up underneath, at the soil line.
A healthy thatch layer is under 1/2 inch. Once it gets thicker than that, it starts causing problems: roots grow up into the thatch instead of down into soil (making the lawn less drought and heat tolerant), water and fertilizer struggle to reach the actual soil, and it becomes a haven for fungal disease and insects.
Which Grasses Build Up Thatch the Fastest
Not all grass is equal here. Based on what we see in Houston yards:
- Zoysia (all varieties) — the biggest thatch-builder of anything we sell. Emerald Zoysia in particular is known for heavy thatch buildup; it’s the most common maintenance complaint we hear about it. Palisades and Zeon build thatch too, just somewhat slower.
- Bermuda — moderate thatch buildup, especially in lawns that are over-fertilized with fast-release nitrogen (rapid growth outpaces decomposition).
- St. Augustine — least prone to problem thatch of the three, though it can still happen with excessive over-fertilization or infrequent mowing.
How to Check Your Thatch Layer
Cut a small wedge out of the lawn (like a pie slice, a few inches deep) with a shovel or trowel and look at the cross-section. You’ll clearly see green blades on top, a spongy brown layer in the middle (that’s your thatch), and soil underneath. Measure the brown layer — if it’s over 1/2 inch, it’s time to dethatch.
How to Dethatch
For light thatch (under 3/4 inch), a dethatching rake (also called a thatch rake, with curved sharp tines) worked through the lawn by hand is usually enough for a typical residential yard.
For heavier thatch, a power dethatcher (vertical mower) — rentable from most equipment rental yards — pulls up much more material in less time and is worth it for larger lawns or thatch over an inch thick.
Steps:
- Mow the lawn shorter than usual right before dethatching (makes the thatch easier to reach)
- Run the dethatcher/rake in one direction, then again perpendicular for full coverage
- Rake up and remove the debris — don’t leave it sitting on the lawn
- Water deeply afterward and follow up with a light application of MicroLife Multi-Purpose to help the lawn recover
When to Dethatch
Late spring, right as the grass is entering active growth (April-May for Houston) — this gives the lawn the whole summer growing season to recover and fill back in. Avoid dethatching in fall or winter; the lawn won’t have time to bounce back before dormancy, and you’ll be staring at a torn-up yard all winter.
Prevention Is Easier Than the Fix
- Mow at the correct height and frequency for your grass type (see our mowing height reference guide) — infrequent, drastic mowing accelerates thatch buildup
- Avoid over-fertilizing, especially with fast-release nitrogen products
- Aerate annually (see our aeration guide) — it breaks up thatch as a side benefit
Just Call Us
If you’re not sure whether what you’re seeing is a thatch problem, a disease problem, or something else, call us at (281) 259-6375 — describe what you’re seeing and we’ll help point you in the right direction. We carry the MicroLife fertilizers that support recovery after dethatching at both our Magnolia and Tomball locations, or get a free quote if thatch damage has left bare spots that need fresh sod.