Removing Lawn Thatch
Thatch causes trouble for your lawn when it exceeds 1/2 inch thick. Cutting through and removing thatch will improve your lawn's health.
Tools and Materials
- trowel or shovel
- tape measure
- stiff lawn rake
- thatch rake, power rake or vertical mower
- lawn fertilizer
- grass seed (optional)
Step 1: Determine Depth of Thatch
Remove a core of soil from the lawn with a trowel or shovel and measure the depth of the thatch, which is the layer of dead grass above the soil line. Excessive thatch prevents air, water and nutrients from reaching plant roots and can leave your lawn more vulnerable to drought, as well as to insect and disease damage. A layer that's 1/2 to 1 inch thick can be removed with a stiff lawn rake; deeper layers of thatch may require a power rake.
Step 2: Know When to Remove Thatch
The best time to dethatch your lawn is just before the grass begins a period of active growth, which is spring for warm-season grasses such as Bermuda, St. Augustine and zoysia. Cool-season grasses such as Kentucky bluegrass are best dethatched just before their period of most active growth, in very early spring or early autumn.
Step 3: Choose a Method for Dethatching
For shallow thatch on small areas, use a stiff lawn rake. For small lawns with more than an inch of thatch, use a special thatch rake. Pull the blade-like tines across the lawn, cutting through the thatch. Work in small sections, and then remove the debris with a rake. Large areas and thick layers call for power rakes or vertical mowers, which are available from rental agencies. To use a power rake, adjust the cutters to slice through just the thatch layer. Check the cutter depth after the first few feet. Run the machine in parallel rows over the lawn and then again at 90 degrees to the first pass. Remove debris with a lawn rake.
Step 4: Prepare Your Lawn
Before dethatching, mow a little lower than usual. If needed, water the lawn to moisten the soil.
Step 5: Aftercare
Water and fertilize the lawn to help it recover from dethatching. To prevent thatch buildup from recurring, adjust the soil pH and alter your lawn care habits if needed (excessive use of water, fertilizer or pesticides are common causes). Overseed with a good-quality grass seed to improve the lawn's health, vigor and appearance.