Thatch is a buildup of organic matter on the lawn grass blades. Over time, a buildup of thatch can stifle the roots and weaken grass, making the lawn less healthy and encouraging weeds to move in. Controlling thatch will keep your lawn lusher and fuller and will reduce your need for pesticides and other forms of maintenance.
Dethatch When the Lawn is Healthiest
Although the need to thatch may be most apparent when the lawn is stressed, putting further strain on it at these times is not advisable. Dethatch in late spring or early fall when the lawn is healthy and green. Avoid high summer time, when the lawn is stressed by heat, and early spring or late fall when the lawn is strained by frost.
Use the Right Tools
Get a thatch tool appropriate for your lawn. For smaller lots, a manual thatch rake should work fine, but for lots over 3,000 square feet, be sure to rent a power rake or vertical mower to make the job quicker. Vertical mowers are better than power rakes according to Bachman's garden specialists, because they pull up more thatch and less grass. Set the blades to a depth of 1/4 to 1/8 inch and go over the lawn at least three times. Go in perpendicular direction every other time, to evenly dethatch your entire lawn.
Clean Up Properly
Dethatch on a day when your lawn is dry, at least 12 hours after a rain shower. Trim the lawn down to about 1 inch in length and either bag or mulch the clippings. When you are done, rake up the thatch and add it to a compost pile.
Thatch your lawn as often as it needs it. If your lawn has good, loamy soil and low to moderate foot traffic, dethatch annually to keep your grass healthy. If your lawn has silt or clay soil, or heavy foot traffic, thatch can build up more quickly and the ground can get compacted more easily. Dethatch twice a year to keep your lawn healthy and green and your soil well aerated.