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Can you cut wet grass?

Will it rain today?

In short: you can cut wet grass, but it's better to wait. Wet blades tear instead of slicing, clump on the lawn and clog the mower, and soft ground ruts under the wheels. After light rain or dew, a couple of dry, breezy hours is usually enough.

The key facts
  • Mow dry grass. The RHS says the grass should be dry so the blades cut cleanly and don't clog.
  • Very wet soil compacts and leaves muddy wheel ruts (RHS).
  • Morning dew counts as wet. On a clear, still night a lawn can be soaking by dawn with no rain at all.
  • Never mow frosty grass, which the RHS warns damages the lawn.

Is it bad to cut wet grass?

Yes, cutting wet grass is bad for the lawn and the mower. Wet blades bend instead of standing up to be cut, so the mower tears them, and every torn tip is an easy way in for disease. The clippings clump into wet mats that smother the grass underneath, and they pack into the mower deck. The RHS's advice is simple: the grass should be dry, so the blades cut cleanly and don't get clogged.

How long after rain can you cut grass?

After a light shower, give it an hour or two of dry weather, longer in the morning or on a still, grey day. After a proper soaking, wait a day or more for the ground to firm up. The grass itself only holds a millimetre or two of water, so the blades dry fairly quickly; the ground under them takes longer. The drying is mostly done by the sun, with wind and dry air helping, so a midday shower clears much faster than an evening one.

Can you mow grass with dew on it?

It's better not to. Dew is just as wet as light rain as far as the mower is concerned, and in autumn it's the most common reason a lawn is soaking at nine in the morning. Grass loses heat to a clear sky overnight and gets colder than the air, so dew forms on it even when the air isn't saturated. Let the morning sun burn it off first: late morning or early afternoon is the best time to mow.

Can you mow when the ground is wet?

Not when it's soft. Even when the blades have dried, soil that's had a lot of rain stays soft, and the mower's weight compacts it and leaves ruts. The RHS warns about exactly that. A quick test: if your footprints sink in or leave a shine of water, leave it for another day.

How do you tell if the grass is dry enough to mow?

Walk across it in your work boots or run a hand over it. If your boots come back wet or your hand does, it's too wet. If the clippings in the grass box would stick together in a ball, wait. Dry grass sprays out of the side of the mower; wet grass dribbles.

When is the best time to cut grass?

Late morning to mid-afternoon on a dry day is the best time to cut grass: the dew has gone and the lawn has had the sun on it. Avoid the hottest part of a summer day, when grass is under stress, and avoid evenings in autumn, when the dew comes back early. Later in the year, the question becomes when to stop mowing the lawn altogether.

How does Weather for Dads know if the lawn is dry?

The mow verdict tracks how wet your lawn is, hour by hour. It adds the rain as it falls, adds dew on clear, still nights, and dries the lawn using the sun (strongest at midday), the wind and how dry the air is. It also keeps a running total of the last two days' rain to tell when the ground will be soft. Then it says NOW, the time the lawn will be dry later today, or the next good day. If it's raining on your head right now, it knows that too.

Sources

Gardening: RHS, how to mow a lawn (dry grass, wet soil compaction, frost).

Our rules: the Weather for Dads mow verdict, explained in the FAQ.

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