Direct answer: A WEN scarifier (dethatcher) typically penetrates only a few millimetres into the lawn: most consumer WEN units are adjustable from about +0.25" above the ground down to roughly -0.5" below the cutting level, which means the scarifying blades cut into the turf about 3–12 mm depending on the setting and model.

Typical depth range

  • Most WEN 2‑in‑1 dethatcher/scarifier units offer an adjustable head height that lets you skim the surface or cut in shallow grooves up to roughly 5–12 mm (about 0.2–0.5") into the soil; the exact depth depends on the model and the chosen setting.
  • Manufacturer guidance and how‑to articles recommend shallow settings for young lawns (around 3 mm) and deeper settings (up to about 5 mm) for older lawns with moss or heavy thatch.

How to set depth safely

  • Place the machine on the lawn and lower the head until the blades or tines just touch the surface, then test a small patch to confirm how deeply they cut. This is the recommended practical approach from product manuals and guides.
  • Use shallower settings in spring (when grass is actively growing) and avoid heavy scarifying in hot, dry periods to reduce stress on turf.

Why depth matters

  • Dethatching tines mostly lift and remove thatch and normally work very close to the surface, while scarifying blades are meant to cut shallow grooves and remove moss and deeper buildup—scarifying is more aggressive but still shallow compared with tillers or cultivators.

Short example (practical)

  • If you have a mature, mossy lawn: start at ~3–5 mm depth and do a test pass; if more removal is needed you can increase depth slightly but avoid exceeding about 10–12 mm to prevent excessive damage.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.