Scalping and dethatching at green-up
Once the lawn is about half green, mow low and rake out the brown winter thatch so light reaches the crowns.
- When
- Apr 15 – May 15 (northern hemisphere) · Oct 15 – Nov 15 (southern)
- For
- Warm-season lawns (Bermuda, Zoysia, St. Augustine)
- Needs
- mower
- Rule
- wm-scalp · Walheim; Scotts; Turgeon
Once the lawn is ~50% green, mow low and rake out the brown winter thatch so light reaches the crowns and green-up speeds up. Bag the clippings.
What scalping is
Warm-season grasses go into spring under a layer of brown, dormant leaves. Scalping means mowing much lower than normal once, and removing that dead layer, so sunlight warms the soil and reaches the growing points. The lawn greens up faster and more evenly.
When
When the lawn is about 50% green and the risk of hard frost has passed, usually mid-April to mid-May in the northern hemisphere. Too early, and a late frost hits newly exposed crowns.
How
- Bermuda: mow down to about 1–2 cm (½–¾ in), lowering the mower in steps over a couple of passes.
- Zoysia: a lighter scalp, to about 2.5 cm (1 in).
- St. Augustine and Centipede: do not scalp hard; just lower one notch and rake out dead material.
- Bag the clippings, then rake or dethatch lightly to lift the remaining debris.
Afterwards
Return to the normal mowing height and give the first feed once the lawn is fully green. Do not scalp if you applied a pre-emergent in the last few weeks.
Sources
- Lance Walheim — Lawn Care For Dummieswalheim
- Scotts — Lawnsscotts
- A.J. Turgeon — Turfgrass Managementturgeon