Dethatching A Lawn

What you’ll need

  • knife
  • power rake
  • garden hose
  • rake

step 1: Determine If Thatch Is a Problem

Take a walk across your lawn and look for dry, dead patches of grass. If it feels “spongy” to walk on, then thatch may be a problem. Take a knife, trowel or shovel and remove a piece of turf (like cutting a piece of pie). Take a large enough sample so you can see the grass, thatch, roots and soil. Measure the thatch, and if it is greater than ½” inch, you should take measures now to reduce it. If the thatch is extensive, move on to step 2. If the thatch is slightly more than ½”, move on to step 6.

step 2: Rent A Power Mower

Check with your local lawn and garden supply store or tool rental store for a power rake (or vertical mower). Most machines have changeable blades: one for vertical mowing and one for power raking.

NOTE: Dethatching will damage a St. Augustinegrass and zoysiagrass lawn. You’ll want to vertical mow these grasses, and be sure the knives on the reel are placed properly. Consult with an expert before doing this yourself.

Instead of renting equipment and doing it yourself, you might consider hiring someone to do it for you. Check the yellow pages or consult with a lawn and garden store in your area for recommendations.

For smaller lawns, you can remove thatch by simply using a cavex rake, which has sharp, rounded tines. Typically these are sold at lawn and garden supply stores.

step 3: Water and Mow Low

Prepare the lawn for dethatching by mowing at the lowest recommended height for your grass type. Next, lightly water the lawn (unless a light rain has fallen recently). The soil should be moist, not saturated — too wet and the equipment could tear up the turf.

step 4: Dethatch The Lawn

Using the power rake with the proper reel and blade settings for your lawn, make several successive passes over the lawn (just like mowing the grass). Do the same thing again, but perpendicular to the first.

If you are using the cavex rake, rake the lawn in one direction, then again perpendicular to the original.

step 5: Rake and Remove the Thatch

Use a lawn rake to clear the removed thatch from your lawn. Rake it into piles and collect it with trash bags or lawn and leaf bags. If you have a compost pile, you can dump the removed thatch in there.

step 6: Optional Step: Core Aeration

If thatch is minimal, you can have your lawn core aerated. This process simply removes “cores” (or “plugs”) from your lawn. Doing so will allow air, water and nutrients to easily reach the root zone where they will aid in the breakdown of organic matter, thus reducing thatch.

You can rent a core aerating machine, or hire a lawn company to do it for you.

Core aerating also helps with compaction. It is recommended that core aeration be done at least once a year for heavily used and maintained lawns — in the spring for warm-season grass and during the fall for cool-season grasses.

step 7: Water and Fertilize

Thoroughly water the lawn to prevent drying out the turf. If you haven’t fertilized recently, now is a good time to do so. Check the  Annual Lawn Care Program that is recommended for your lawn.

To have a nice lawn, you should do these things: Mow high and often, be sure your lawn gets plenty of water, and follow a proper feeding schedule.