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The Curious Bag
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<h4 class="dechead">On One Hand: De-thatching Annually Prevents Problems
Thatch, an accumulation of organic debris on the surface of a lawn, can build up over a period of years to form a thick mat. Thatch can restrict the movement of water, air and nutrients, and it provides a habitat for pests and disease. Preventing excess thatch is easier than removing it, according to the University of Maryland Cooperative Extension. De-thatching annually prevents a thick buildup.
On the Other: Some Thatch Is Beneficial
A light layer of thatch is beneficial, according to the University of Minnesota Extension Office. Lawns do not need to be de-thatched every year, and some never need de-thatching. One half to three-quarters of an inch of thatch can protect the crown of the grass and help the lawn retain moisture.
Bottom Line
Inspect the lawn to determine when to de-thatch. Thatch is not harmful until it exceeds one half inch in thickness. De-thatch if grass looks green on top but dry underneath, or if there are dry spots despite regular watering.
Source:
University of Maryland College of Agriculture and Natural Resources: Scratch Out Thatch
University of Minnesota Sustainable Urban Landscape Information Series (SULIS): Lawn Thatch
Oregon State University Extension Service: Spring is the Best Time to De-Thatch Your Lawn
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