Lawn
Grass Clippings Do Not Cause Thatch
Leaving clippings on the lawn returns up to a quarter of its annual nitrogen and does not build thatch.
Thatch is the layer of slowly decomposing lignin-rich tissue — stolons, rhizomes, crowns, and roots — that accumulates between the green blades and the soil. Grass leaf blades contain roughly 80% water and very little lignin, so they decompose within two to four weeks.
Multiple university turf trials put the nitrogen returned by clippings at around 20-25% of a lawn's annual requirement. The real causes of thatch are over-fertilisation, over-watering, compaction, and low soil biological activity.
Put this into practice
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More facts like this
- Late Summer Beats Spring for Overseeding Cool-Season LawnsSeed sown in late summer germinates into warm soil with less weed competition and two cool growing seasons ahead of it.
- Mowing a Lawn Too Short Weakens It More Than Skipping a WateringScalping a lawn to save mowing trips stresses the grass more, and for longer, than a week of missed watering would.