A robot mower trims a little every day instead of a lot once a week. That gives a dense lawn and fine clippings that feed the soil, but only if the height and the schedule suit the season.
What cutting height should you set?
The same height you would cut to with a normal mower. For a fine ornamental lawn that is 3 to 4 cm, for a family lawn 4 to 5 cm, and in shade 5 to 6 cm. Because the robot runs almost every day, it never takes off more than a third, so there is no need to go lower to get a neat finish. In spring, start high and lower by no more than 5 mm a week, and in a drought raise it by 1 to 2 cm. More on heights in what height to cut grass.
How many days a week should the robot run?
This is the schedule the What a Green Lawn app shows for a robot on a lawn in Manchester. The app keeps every window between 07:00 and 20:00 and ends it at least half an hour before sunset, so the hours shift a little with where you live:
| Month | Days a week | Time window |
|---|---|---|
| March | 3 | 10:00 to 16:00 |
| April | 5 | 08:00 to 19:00 |
| May to July | 7 | 07:00 to 20:00 |
| August | 6 | 07:00 to 19:00 |
| September | 5 | 08:00 to 18:00 |
| October | 3 | 10:00 to 16:00 |
| November | 1 | 11:00 to 15:00 |
| December to February | Stored |
Treat it as a starting point and cut back when growth slows, for example in a dry July.
What does the app show for September?
With robot selected, the calendar shows the month’s mowing with days, height and time window:
The height is your own target for the month, here 4.0 cm. In September the first leaves fall and collect under the robot and in its wheels, so clean it more often and clear leaves off the lawn.
Should a robot mower run at night?
No. Hedgehogs forage at dusk and at night and curl into a ball instead of running from a mower, and wildlife groups advise running robots in daylight only. The app does that for you: every window ends by 20:00 and at least half an hour before sunset, and starts half an hour after sunrise.
What about rain and soft ground?
Many robots have a rain sensor and head back to the dock. From October the ground softens and the wheels can slip and rut, which is why the app drops to three days a week. If the robot gets stuck or leaves tracks, skip the day.
When should the robot come in for winter?
When the grass stops growing, usually in November. Clean the blade disc and underside, charge the battery to about half, and store it dry and frost-free from December. In late winter, fit new blades and check the boundary wire before it goes out in March. See first and last cut of the year.
What a Green Lawn shows the robot schedule for every month in the calendar, so you know when to turn it up and down.