Managing Thatch for a Healthy Lawn or Turf

Every spring when wandering through the lawn and garden department at your local home improvement store you probably see a selection of thatching rakes and rental vertical mowers. If you’re wondering what they might be used for, you’ve come to the right place.  Thatch is a vital part of your lawn’s structure, but just like the green blades of grass, thatch requires some maintenance to support a healthy turf able to withstand kids, football games, or a round of golf.

What is Thatch?

Thatch is the dry accumulation of brown bits of grass and roots that you see beneath the lush green blades.  This tangled mass is made up of dead roots, dry stalks, and other parts of your grass that resists the rotting process.  It is not made up of just grass clippings or even crushed leaves.  The top part of the grass that you mow on a regular basis and fallen leaves from your trees break down fairly quickly and are easily integrated back into your soil.

How Much Thatch is Too Much

Your lawn does need some thatch to provide shade for the roots and help to prevent immediate evaporation of rainwater, allowing it to seep into the ground.  A half-inch of thatch is considered just about right.  If your yard has developed an inch or more of matted, dry material you can harm your lawn further when your mower sinks into the grass and cuts it too close to the crown. Thick thatch interferes with the ability of the plant to grow, blocking sun and water from reaching the soil. It can even affect microorganisms and insects that are part of a healthy yard.

What Causes Thatch Buildup?

The cause can be as simple as which grass you selected for your turf. Creeping red fescue, Kentucky bluegrass and bent grass produce more of the stems that are harder to biodegrade.  Thus, if your yard has a single type of grass planted from among those listed, you will struggle to keep your thatch to a minimum.  Clumping grasses such as rye and tall fescue do not produce as much thatch, but don’t always create that smooth and even turf that is sought after. A blend of grass seed can help to minimize the potential problem while still maintaining the attractive appearance.

Over-fertilization and the persistent application of some pesticides can cause existing grasses to start producing excessive roots and stems.  The pesticides can harm microorganisms in the soil, threatening the grasses which then enter a hyperactive growing period.  More thatch is produced by grasses that have gone to seed.

How to Remove Excess Thatch

Dethatching can be a tiring process, as there is no simple chemical you can spray on the yard.  It must be physically removed. A thatching rake can be used to pull up the dry and matted material.  Care must be taken that you are not ripping up the grass, but still getting down to the point where you are able to remove the thatch.  Remember that some thatch is good, so you don’t want to dig down to the bare earth.

It’s best to dethatch in the spring before the growing season has begun or in the fall after the leaves have turned, but before the first frost.

There are vertical mowers available and are a good investment for landscaping companies and municipal maintenance teams.  These are able to de-thatch a large athletic field, parks or large yards in a shorter amount of time.  For the homeowner, you may want to rent one as this is not something you will need to do every year.

Managing St. Augustine and Other Creeping Grasses

For many homeowners and landscapers who live in warmer climates, a popular option for creating a lush thick lawn is the use of St. Augustine or Bermuda Zoysia grass. These species grow differently from other grasses, as their stems grow horizontally along the ground sending their roots down into the soil as they spread.  By its nature, St. Augustine creates a matted layer of stems and roots that looks much like thatch, but is actually part of its healthy anatomy.

De-thatching Can Harm Creeping Grasses

Left to its own devices, St. Augustine grass will continue to build a thicker and thicker layer of matted stems and roots, raising the green blades higher and higher over time. In order to maintain this dense, deep lawn you may have to raise the deck of the mower to a higher setting to avoid cutting into the thatch.  If you took a thatching rake or vertical mower to this dense mat, you could end up killing the lawn as you start to rip out its roots and expose the crown of the grass plant.

Consulting a Professional May Save Your Lawn

If you are faced with an aging lawn seeded primarily with a warm-weather grass like Bermuda Zoysia or St. Augustine, or are uncertain what kind of grass is growing in your thickly thatched yard, you may wish to call your local landscaper for some tips and information. They may be able to recommend a plan of action that can further extend the life and look of your yard.  It is also possible that your St. Augustine grass has become so thickly matted over the years that it is time to have it removed and start from the beginning.

Preventing a Recurrence

If your turf is entirely made out of creeping fescue or bluegrass, you may wish to introduce a blend of rye and tall fescue to help mitigate the return of too much thatch.  Follow your fertilizer schedule carefully without adding an extra application, as you are throwing off the plants’ natural ability to create a healthy environment. Have the ph level of your soil tested and treat it accordingly to help support the microorganisms that help to breakdown the bits of grass that turn into thatch.

For more information on your lawn and how thatch effects it, visit the Duda Sod website.