Mow high in summer: why 5–6 cm beats a short cut

Most lawns are cut too short in summer because a short lawn looks tidy on the day. The grass pays for it over the following week: a shorter blade means less leaf to photosynthesise, less shade over the soil, and a root system that shrinks to match the top. In July that is exactly the wrong direction.

Why taller

A 5–6 cm canopy shades the soil surface. Cooler soil loses less water, so the lawn holds up longer between the deep waterings the schedule sets for this season. Root depth tracks leaf height — leave more leaf and the roots follow the water down. And crabgrass seed needs light at the surface to germinate; a dense, tall canopy is the cheapest pre-emergent there is.

In heat, raise the height to 5–6 cm — taller grass shades the roots and holds moisture.

The one-third rule

Never remove more than a third of the blade in one pass. If the lawn has got to 9 cm, cut to 6 — not to 4. Taking more than a third shocks the plant, browns the tips and opens the canopy to weeds. If you are behind, take it down over two cuts a few days apart.

Deck, blade, clippings

Set the deck to its second-highest position and check the actual cut with a ruler — mower markings are optimistic. Keep the blade sharp: a torn tip loses water and browns within a day in heat. Leave the clippings on the lawn unless they clump; at this height they return nitrogen and disappear in a couple of days.

What the schedule does with this

Pratela issues this as a recurring summer work order for cool-season lawns, every 7–10 days, and holds it when the soil is waterlogged after heavy rain so the mower doesn't rut the lawn. Mark it done and the next mow lands a week out; a growth surge can bring it forward. Warm-season lawns get their own mowing rule with a height per grass — Bermuda 1.5–4 cm, Zoysia 2.5–5 cm, St. Augustine 6–10 cm — and the app picks by your grass type.