Fall is the Time to Dethatch Lawns in the Midwest

Thatch Layer

The thatch layer is in the middle between the green grass & the soil.

Fall is the best time to dethatch the lawn in the Midwestern area.

Thatch is a layer of dead grass, crowns, and surface roots that accumulate at the surface of the soil just under the turf. Allowing a small layer, about ½ an inch will act as a great natural mulch, but any more than that will cause the following:

  • Tight, spongy mat that will choke the crowns of the living grass
  • Inhibits the decomposition of organic debris around the grass
  • Prevents good circulation of air
  • Can provide breeding grounds for harmful pests
  • Can harbor diseases such as fungus

The most common cause of thatch is compacted soils. Grass roots will seek air at the soil surface and then die. Other causes:

  • Overuse of fast-acting nitrogen fertilizers causes rapid growth at the expense of a good root system. These also tend to acidify the soil, repelling beneficial thatch-eating earthworms.
  • Overwatering drowns microorganisms in the soil that decompose thatch
  • Mowing too closely or taking off more than one-third of the blade causes more thatch

Four ways to dethatch your lawn:

  • Buy a manual thatch rake and break your back (yup, this way is for masochists…)
  • Rent a dethatching machine called a power rake or a small tiller that has dethatching tines
  • Attach dethatcher tines to your lawnmower
  • Spray biological products on the thatch to decompose it

After dethatching, the lawn is susceptible to drying out. Be sure to water the lawn every few days for three weeks. Ten to two weeks after dethatching, spread a slow-acting, granular fertilizer over the lawn to stimulate growth of new grass. Read the label closely.

Help prevent the development of thatch by aerating your lawn in the SPRING to encourage deeper root growth, apply slow-acting fertilizers, and provide grass clippings (YES, I said leave the clippings on the lawn, do not pick them up!) as an organic mulch to encourage earthworm activity.

Grass clippings do not cause thatch. Don’t make me repeat that!!

© Ilex Farrell ~ Midwestern Plant Girl

2 thoughts on “Fall is the Time to Dethatch Lawns in the Midwest

  1. Pingback: Monday Memories 9-28-2015 | Midwestern Plants

  2. Pingback: Monday Memories 9-12-2016 | Midwestern Plants

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