When thatch builds up on top of the soil, it can prevent essential nutrients, water and oxygen from reaching the roots of your lawn. Thatch becomes excessive when it exceeds 1/2 inch deep. Pests and disease can also dramatically increase in your lawn when thatch becomes excessive. Thatch is formed when turfgrass stems and roots build up faster than they can decompose. Thatch is closely linked to overwatering and heavy applications of nitrogen fertilizer. To maintain a healthy lawn, you need to dethatch your yard when thatch becomes excessive.
Mow your lawn an inch shorter than you normally would mow. Lightly irrigate the lawn to moisten the soil surface.
Rent a dethatcher from your local rental store or home and garden center. Read the operation manual carefully to learn how to operate the machinery.
Run the dethatcher back and forth across the lawn until the entire lawn has been covered. Rake up all the debris and discard.
Run the dethatcher back and forth across the yard again, perpendicular to the direction you went the first time. Repeat removal of the debris and discard.
Fill your broadcast spreader up with your selected grass seed. Set the dial on the spreader to the setting indicated for overseeding on the grass seed bag.
Walk back and forth across the entire dethatched lawn and broadcast the grass seed.
Rake the seed into the top 1/16 to 1/8 inch of soil. Roll with an empty lawn roller to press the seed into the soil.
Apply a starter fertilizer to the entire area with your broadcast spreader. Apply at the indicated rate on the starter fertilizer.
Topdress the entire area with 1/4-inch layer of soil, compost or mulch to hold the moisture in.
Set up lawn sprinklers and irrigate the area. Keep it constantly moist, but not soggy. Start with an irrigation schedule of two to three times per day with each cycle irrigating for 5 to 10 minutes. Adjust up or down depending on local conditions.
Resume a normal irrigation schedule after the first mowing of your new grass.