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What is a robot lawn mower?

By Martin Pratt

Robot lawn mowers cut the grass for you, but they aren't cheap. Are they worth the extra money or should you buy a conventional lawn mower or ride-on mower instead?

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The growing trend of household appliances that take the hassle out of everyday chores has extended to the garden with robot lawn mowers. They work in much the same way as robot vacuum cleaners that clean up messy floors without any input from the owner, but robot mowers take care of your lawn.

With some models capable of 5,000sq m metre plots or more, robot mowers are a viable alternative to ride-on mowers for anyone with a lot of ground to cover who doesn't want the bother of mowing themselves. They also appeal to anyone wanting a no-fuss way of keeping their garden looking neat and tidy, and to less-able gardeners who may struggle to push around a heavy mower.

You'll need to pay a premium for the luxury of having an robot mower cut the grass while you recline on a Sunday afternoon, though. Robot mowers are expensive, with many costing significantly more than even the priciest conventional mowers.

In this guide, we'll tell you everything you need to know about robot lawn mowers, including how they work, how much you should pay for one and which brands produce robot mowers. 

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How do robot lawn mowers work?

Once set up, robot mowers are completely autonomous. There's no need to switch them on, keep an eye on them and, of course, there's no pushing required. The mower will come on a times scheduled by you, cut your grass and return to its dock to charge its battery ready for the next mow.

 

Once set up, robot lawn mowers are completely autonomous. There's no need to switch them on, keep an eye on them and, of course, there's no pushing required.

They work by creating a map of your lawn to make sure they don't go over the edges into your borders. When they cut, they do so in a random pattern and it may look as though your mower has gone haywire, but it won't stop until it has cut every square inch of your lawn. The downside of this seemingly haphazard mowing is you won't get a striped lawn. 

Most have sensors, so they'll stop if they encounter any obstacles and continue cutting in a different direction. So it's best to remove any large obstacles, such as children's toys and garden tools, but odd-shaped lawns or bushes and trees planted throughout your garden shouldn't be an issue for a good robot mower. 

There's no need to empty them either. Rather than collecting the cuttings, the mower cuts them up finely and leaves them on the lawn as mulch to encourage healthy grass and help prevent weeds.

How to set up robot lawn mower 

 

Assuming that you don't have any issues down the line, setting up your robot lawn mower could be the first and last time you interact with it. Most of the set-up is done on the device itself, or a smartphone app, but there is a more fiddly hoop you need to jump through.

Before you let your robot mower loose on your garden, you need to lay a perimeter wire so the mower can detect the boundaries. The wire also helps orientate the mower and guide it back to the charging dock. The wire is secured by pegs and is fairly inconspicuous, but some manufacturers and dealers will even lay the wire underground if you want it to be fully invisible.

The wire connects to the charging dock, which requires mains power, so make sure you set it up within reach of an outlet. Some manufacturers and dealers will install the wire and charging dock for you.

Once your wire is down you can start programming your mower. Generally, this will mean setting the date, time and how often you want it to cut the grass. There are some smart mowers that connect with an app on your smartphone, too. You can use the app to control the mower if you think the lawn needs an ad hoc trim, otherwise you'd need to use the controls on the mower itself.

What to consider when you're buying a robot lawn mower 

  • How big is your garden?

Every robot mower has a maximum lawn size that it can cut. This is usually measured in square metres. Don't assume that a mower that covers less distance, or has less battery life, can do your entire garden in two trips. The mower may not come with enough perimeter wire to cover a bigger garden or it may not be able to travel far enough from its dock.

  • Are there any slopes in your garden?

Most robot mowers can handle a bit of a hill, but some can manage steeper inclines better than others. If your garden has any slopes then make sure the mower you choose has the power to get up them and keep cutting as it goes. You'll find the maximum angle each mower can navigate in our reviews.

  • Do you need a mower than functions in rain?

If your garden gets a lot of rain, then it may be worth investing in a mower that can cut grass in wet conditions. Some mowers can't cut wet grass, while others return to their dock automatically when the rain starts falling.

  • Do you need a mower than can handle multiple zones?

If your lawn is separated by fences of paths then you may need to buy a multi-zone mower. This is also useful if you'd like your mower to do the front lawn as well as the back. Some models ask you set a base zone, which is mowed automatically to the schedule, while the numbered zones require you to manually start the mower and tell it which area to cut. If the mower can't access one of your areas, then you'll need to carry or wheel it there yourself.

  • Does it have fixed or pivoting blades?

Both types should be more than capable of cutting grass, but they aren't equal if they come into contact with something harder. Pivoting blades can move if they come spin up against any hard objects whereas fixed blades don't, meaning they are more likely to get stuck on anything solid in your garden, such as toys.

  • What's the battery life?

Generally, the larger mowers that cover more ground also have the largest batteries, but machines designed for a smaller garden should be able to trim the whole thing on one charge. If you've got a multi-zone mower than it may need to charge between areas. Some mowers can charge to full in 45 minutes while others take a whopping 16 hours, so you may need to wait more than half a day before you can finish all of your zones. 

Which brands are making robot lawn mowers? 

Some of the biggest brands in lawn mowers are turning their hand to robot models while others have yet to release any.

Bosch

Bosch has two robot lawn mowers, the Indego 350 and Indego 400 Connect. Both models are similar, but the 400 can handle lawns up to 400sq m, while the 350 has a maximum lawn size of 350sq m - hence their names. The Indego 400 also has an app that let's you control your mower remotely. The battery lasts 30 minutes on both models and only takes 45 minutes to charge to full in the dock. They can handle inclines up to 15 degrees.

Bosch mowers are the only models that cut the grass in parallel lines. Although it won't leave stripes, this way of mowing reduces lawn stress.

Both mowers have adjustable blades, so you can have grass as short as 30mm and as long as 50mm.

The Indego 350 will set you back around £800, while the Indego 400 costs slightly more at £850. Both these mowers are on the cheaper end of spectrum as some models from other brands cost as much as £2,500.

You can read more about these mowers in our Bosch Indego first look review.

Robomow

With eight different mowers, Robomow has a comprehensive range that covers relatively low-cost models suitable for modest lawns all the way to expensive machines that can mow almost an entire football pitch.

The RX range has two models designed for smaller gardens up to 300sq m, although the cheaper of the two, the RX12U, doesn't have a mowing schedule so you'll need to use the menu on the mower when you want it to start cutting the grass.

 
 

Robomow has a comprehensive range that covers relatively low-cost models suitable for modest lawns all the way to expensive machines that can mow almost an entire football pitch.

 

The RC range includes three models which can mow gardens up to 2,000sq m and the RS range can cover more than an acre of ground.

Prices range from £599 for the entry-level RC all the way to £2,999 for the top-of-the-range RS model. The RC range costs between £1,199 and £1,899.

See what we thought of one of Robomow's mid-range models in our Robomow RC304 first look video.

Flymo

Swedish company Flymo currently has one robot lawn mower in its range. The 1200R can take care of lawns up to 400sq m and can handle 14-degree inclines. Like the Bosch mowers, the 1200R has adjustable blades than can cut grass to anywhere from 20 to 50mm.

The 1200R is one of the cheapest robot mowers around at £699. You can see what we thought of it in our Flymo 1200R first look review, which includes a video of the mower in action.

Husqvarna

Swedish company Husqvarna's robot mowers aren't the cheapest, but the brand is known for quality. Prices start at £1,000 for the Automower 105, which can handle plots up to 600sq m, all the way to the £3,100 Automower 450X, which can mow a lawn up to 5,000sq m.

In total, Husqvarna has seven robot mowers on offer and they are particularly good on slopes. The £1,400 Automower 310 can handle inclines up to 40%, while the high-end ones can manage 45%. If your garden is particularly uneven, with several banks, then a Husqvarna mower could be a good option.

The pricier mowers have some extra features, too, such as mowing the grass more often when it has been raining or the ability to control your mower from your smartphone.

John Deere

John Deere only offers one robot mower, the Tango E5 Series II. This heavy-duty robot mower looks robust and bulky. It costs £2,130 and, for the money, you'll get a mower that can cut grass come rain or shine and scale inclines of up to 36%.

As you might expect, given the price, the E5 Series II can mow a large plot. 2,200sq m is the maximum size and it can run for 90 minutes on a single charge.

How much should you pay for a robot lawn mower? 

You can pay a small fortune for a robot lawn mower, but depending on the size of your garden you may not need to. The pricier mowers, which can cost upwards of £2,500, can cover huge surface areas of 5,000sq m or more whereas cheaper models, which you can buy for around £600, can manage lawns of around 400sq m. Consider which features you need, such as the ability to tackle slopes or to control the robot mower from your smartphone, as these will help dictate your budget.

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