When Is a Good Time to Dethatch My Lawn?

When to Dethatch

• Gardeners can tell it is time to dethatch when their lawn begins to feel bouncy. The feeling is the thick layer of thatch that has accumulated. To know how much thatch you need to remove, you can press a measuring stick through the grass to the soil. A layer over 1/2 inch should be removed from the lawn. You can also check by cutting out an area of lawn with a spade and looking at the brown layer that is between the soil and turf.

Time of Year

• Spring is a good time to remove thatch for warm season grass types. It is important to remove thatch before you fertilize. If you fertilize before you remove your thatch, you will waste fertilizer because it will not be able to absorb into the soil and reach the grass roots. Fall is an optimal time to dethatch for cool-season grass. By dethatching before you conduct your fertilizer, herbicide and pesticide applications, you may avoid the need for so many chemicals.

Time of Day

• It is a good idea to start your project early in the day before the heat. In addition, wet your grass before you push a power rake or dethatch over the lawn. Moist soil will aid in ripping the thatch from underneath the grass blade. You do not want to have wet grass late in the day. Moist grass combined with low nighttime temperatures raises the risk of your grass contracting a fungal disease.

Mowing

• Mowing the lawn before dethatching will help the blades of the dethatcher pulling up the thatch. However, dethatching causes a lot of stress on grass. Do not take off more than a third of the grass blade when you mow. If you have tall grass, mow one day and wait a few days to mow again to prevent harming the grass' root system.