Robotic Lawnmowers - Everything you need to know - Grand Designs Magazine
Automatic lawnmower in modern garden

Robotic Lawnmowers – Everything you need to know

A robotic lawnmower might just be the best labour saving gardening device

By Harry Duncton |

Truly, we have embraced the idea of home automation. Smart lighting, video doorbells, and robot vacuum-cleaners are now common sights in homes across the country. Up until recently though, these smart technologies hadn’t reached past the back door. This trend is changing rapidly however, and robotic lawnmowers are now one of the hottest gardening products to trundle across UK lawns.

According to the Royal Horticultural Society, a neat lawn needs to be cut weekly or fortnightly during the growing season. And for many, the prospect of trudging behind a mower is rather unpleasant.

If mowing the lawn fills you full of dread, the solution lies in technology. A robotic lawnmower promises to take all the hard work out of keeping your lawn looking great, and can even help improve the look and feel of your grass through the season, helping restore a lawn after winter. Not only that, but they’re designed to free up shed space, and won’t annoy your neighbours either. You can even control some of them via apps, while you stay indoors in the warm.

But are robot mowers just the next home technology fad?

Let’s take a closer look at these small robots that live to tend our lawns. Ranging from basic robot mowers that slavishly follow wires, to slick-looking devices that utilise space-age technology, choosing the right robot for you is a challenge.

The Robotic Mower Revolution

Let’s start off with a bit of garden mathematics- the average garden size in the UK is 140 square metres, or roughly half a tennis court. To mow this size lawn with a standard push mower will take around ten minutes (that doesn’t include the time spent untangling cords, dumping grass clippings, and putting the mower back in the shed). So, If you’re mowing each week between March and October, you could spend up to six hours keeping an average-size garden tidy.

If just reading that makes you feel tired, a robot mower might be the solution to the tedious task of keeping your grass looking great. But are they really the best thing to happen to a garden since the electric mower?

One of the most obvious benefits of a robot mower is that you don’t have to do the mowing. For someone with a large lawn, they save a significant amount of time. For people with limited mobility, they can help retain independence in the garden. And for people who are time-poor, a robot mower is a “fire and forget” solution to keeping your grass short while you’re busy doing other things.

The less obvious benefit of an auto mower is that they’re not loud. The Segway Navimow i Series is almost whisper-quiet at just 58 dB, equivalent to a refrigerator running; and most robots are similarly as quiet, so you can set them to mow at any time of the day or night without worrying your neighbours. And, because they live in their own docking station or garage, robot mowers don’t use up valuable shed space.

Automatic robot lawn mower cutting green grass on beautiful land

So, how do robot mowers work, and what do they offer that conventional mowers don’t?

Setting Clear Boundaries

Some robot lawnmowers rely on a physical boundary to define the size and shape of your lawn.

A wire, either sunk into the ground or laid on top, works like an invisible fence to stop the robot from decimating precious flowers or wandering off down the road. You can also use this boundary cable to define multiple lawns, using the wire as a guide between different spaces.

Installing these boundary wires can be tricky and time-consuming, especially if you have created different zones in your garden. If you have more than one lawn surrounding your home, you might struggle to install a boundary wire without it becoming an eyesore.

Setting up a boundary wire is a morning’s work with a mallet and a calm disposition. If you want to avoid this step, some mowers, like Stihl’s iMow series, have the option for a dealer installation package (Stihl has more than 700 approved dealers across the UK) at an additional cost, which could well be worth the expense to get the installation right.

More modern and tech-heavy robot mowers have done away with physical boundaries altogether though. Using a blend of AI technology, clever cameras, GPS satellite data, and even military-spec LiDAR systems, they can guide themselves around multiple lawns of almost any shape with minimal user input. These can struggle with more complex layouts, and many don’t cut as close to the boundary as a robot with a boundary wire.

How are robotic lawnmowers different to conventional ones?

One of the first questions that comes up about robot lawnmowers is “Where’s the grass collection box?”. And the answer is, they don’t have one. The entire mowing concept behind these robots is rather different compared with traditional mowing.

The fundamental difference between traditional push-behind mowers and their new robot rivals is how much they cut off during each session. Conventional mowers handle grass growth with weekly cuts, while robot mowers nibble at your lawn daily.

With a traditional walk-behind mower, you might mow once a week during peak grass-growing weather. You’ll typically take off a few centimetres of growth, while a robot mower will go out every morning and take off just a millimetre or two.

They can improve the health of your lawn

Robot lawnmowers can condition your lawn while they keep it looking tidy. Using tiny, double-sided razor blades, they trim the top off the grass blades and let the tips fall back into the grass.

This has two big benefits for both you and your garden.

The first one is that you’re not forced to deal with mountains of grass clippings that can be a pain to dispose of. A big pile of grass cuttings will smother a compost bin and end up as a slimy mess.

The second benefit is that the tiny grass clippings function as a natural fertiliser for your lawn.

Most robotic lawnmowers are “mulching mowers”. This means they leave the clippings behind. This ready-made mulch helps with water retention, suppresses weeds, and even pushes nutrients back into the lawn. It’s a win-win situation for the lawn and the lazy gardener as well.

Man swaps blades for robotic lawn mower

Not so hidden drawbacks

The first thing that might put you off a robotic lawnmower is the price. Feature-rich mowers from big garden equipment brands like Husqvarna cost upwards of four or five thousand pounds. That’s not an insignificant investment into a piece of home technology.

Even the more budget-friendly and basic robots, like the excellent Flymo EasiLife Go, will set you back several hundred pounds. Compare that to a standard electric lawnmower at fifty quid, and you need deep pockets to get into the automated mowing game.

And let’s face it, robot mowers are still relatively new technology. Even the most advanced AI-assisted mower, bristling with cameras and sensors as well as real-time GPS data gets lost. Or stuck under a garden bench. Or mows through your prize zinnias thinking they were a patch of weeds.

Even “smart” technologies have their limitations. Premium robot mowers advertised as “drop and go” machines need help to get started. You’ll still spend time setting up and fine-tuning mowing programmes before a robot mower will provide a decent cut. And, even the best robot lawn mower leaves gaps around the border that it can’t touch, so you’ll still need a grass trimmer and will need to tackle the edges manually.

Are robotic lawnmowers worth it?

The deciding factor in making a big purchase like this comes down to how much you value your time. Put simply, if you hate mowing the lawn, and you don’t mind splashing out on an automatic mower, it’s worth it. And, as they mulch, a robot lawn mower can improve the quality of your lawn with very little effort.

But if you have a strange shaped garden with lots of obstacles, it might not even work. Robotic lawnmowers are getting better at their job and getting cheaper as more are developed. As we head into a future of helpful robots performing mundane tasks around the home and garden, it’s up to you if you want to embrace the change now, or later.