Do grass clippings cause thatch and lawn disease?

No. Research has shown that grass roots are the primary cause of thatch, not grass clippings. Thatch is composed primarily of roots, stems, rhizomes, and other plant materials. These plant materials contain large amounts of lignin (fibrous material) and decompose slowly. Grass clippings are approximately 80-85 percent water with only small amounts of lignin, and decompose rapidly.

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