Springtime brings new growth throughout Georgia, and as new shoots begin pushing past the old ones, residents often fear what will happen to last year’s leaves and stems. Any accumulation of this material is often misidentified as a thatch layer and generates a lot of questions about dethatching or other remediation methods.
The truth of the matter is, that most lawns don’t have enough thatch to warrant the risk of removal, and other methods should be considered first before a homeowner resorts to verticutting or power raking. Here is a breakdown of thatch from the lawn care team at Nature’s Turf.
What is Thatch?
Thatch is an accumulated layer of plant materials, generally harder tissues, that create stresses like increased incidence of fungal infection or an inability to wet the soil beneath it (known as hydrophobicity). All turf has some thatch. The good news is, grass blades don’t contribute to it. While all plant tissues have cellulose (the structural component that makes wood, wood), some have much more than others. Leaves tend to have relatively small amounts of cellulose in their cells when compared to stems, roots, or stolons. This means that leaves are generally easily broken down by microorganisms in the soil, and can be great sources of nutrients when allowed to break down. (Pro Tip: When mowing weekly, you don’t need to bag your clippings. There is really only one time you should bag them, but we will get there later in this blog.)
Plant structures like stems, roots, and stolons are much higher in cellulose and are significantly harder for soil microbes to break down. If poor turf management strategies are used, these materials will accumulate. As the dead materials slowly degrade, and the live materials intertwine them, you end up with a thatch layer.
Why Are Thatch Layers Bad?
Thatch takes a stress condition like excess moisture or drought and magnifies them. In areas of a landscape that stay too wet, thatch will hold onto that water for a prolonged period of time. This creates conditions favorable for fungal growth. Soils that stay too wet also have low oxygen levels that result in issues like root rot.
Conversely, areas of the landscape that stay too dry become exceptionally hard to rehydrate. Organic materials often become hydrophobic when they dry excessively, and this is true for excess thatch. Areas that experience this will have drought-like symptoms at unlikely times, but will also suffer from nutritional deficiencies due to the reduced ability to get nutrition into the soil profile, or the water needed to make this nutrition mobile and available for the plant to absorb.
How Do I Get Rid Of Thatch?
Instead of focusing on removing thatch, focus on good maintenance tactics that will slow or stop excess thatch from forming. So much emphasis on lawn maintenance is placed on fertilization and weed control. While a healthy, clean lawn depends on both of those things, the health and well-being of turfgrass is also exceptionally dependent on mowing and watering well.
If you’ve read any of our other blogs (please do), you will see how much emphasis we put on good mowing habits. Turf that is mowed weekly at an appropriate height (1.5-2 inches) sustains minimal injury from each mowing, allowing it to thrive. Mowing in this way also reduces the amount of clippings produced in each mowing, and avoids cutting stem materials. For Bermuda lawns, they are best if only scalped once a year in the spring. This is the only time I encourage you to bag your clippings. If you have Zoysia, a height reset to 1.25 or 1.5 inches to start a season is much safer than scalping, and clippings should be bagged when doing this as well.
Arguably more important than any other maintenance practice is watering. Plants can go a long time on low fertility. They can even sustain for a period of time with low light. They don’t last long with insufficient water. The schedule and strategy with which water is delivered can have major impacts on thatch formation too. Watering a few minutes daily makes for shallow water availability. Plants grow roots where there is water. Shallow water means shallow roots and accelerated thatch formation. Watering deeply 2-3 times a week allows more depth for water percolation, resulting in a deeper root system with better dispersion and less shallow density.
It should be acknowledged that over-fertilization can result in excess, accelerated growth. If you have a service that provides fertilization, please consult them before doing any additional fertilization. There is a lot of good science around the nutritional needs of your lawn, and a competent lawn care company should consider that when developing a nutrition program.
But What If I Already Have Thatch?
If you’ve noticed symptoms like hydrophobicity, and pulled a profile to find an exceptional thatch layer, it may be time to act. Most of the time, the safest way to accomplish this in a home lawn is subsequent annual aerations. Aeration provides many benefits to the lawn, but also the health and quantity of the microorganisms tasked to break down old plant materials. The added benefit of proceeding with aeration compared to other methods of thatch removal is relative safety for the lawn.
De-thatching using verticutting machines, power rakes, and other mechanical methods can be injurious and should be done carefully. While this task can be accomplished in other, less-invasive ways, these methods have a place in extreme cases. Weighing the pros and cons against the severity of your thatch layer is important, and care should be taken before and after the act of thatch removal.
Important Takeaways:
- Thatch is an accumulated layer of plant materials, generally harder tissues, that create stresses like increased incidence of fungal infection or an inability to wet the soil beneath it (known as hydrophobicity).
- Plant structures like stems, roots, and stolons are much higher in cellulose and are significantly harder for soil microbes to break down.
- Thatch takes a stress condition like excess moisture or drought, and magnifies them.
- In areas of a landscape that stay too wet, thatch will hold onto that water for a prolonged period of time.Conversely, areas of the landscape that stay too dry become exceptionally hard to rehydrate.
- Instead of focusing on the removal of thatch, focus on good maintenance tactics that will slow or stop excess thatch from forming.
- Turf that is mowed weekly at an appropriate height (1.5-2 inches) sustains minimal injury from each mowing, allowing it to thrive.
- The schedule and strategy with which water is delivered can have major impacts on thatch formation too.
- Most of the time, the safest way to accomplish this in a home lawn is subsequent annual aerations.
- De-thatching using verticutting machines, power rakes, and other mechanical methods can be injurious and should be done carefully.
- Weighing the pros and cons against the severity of your thatch layer is important, and care should be taken before and after the act of thatch removal.
