Robot lawn mower questions and answers

Mostly not for mowing itself, but many connected mowers have a paid data plan for the extras once a free period ends. It's worth reading the small print before you buy.

The cost usually comes from the 4G connection built into many wire-free mowers. That link carries remote control from anywhere, GPS anti-theft tracking and, on network RTK mowers, the satellite corrections the mower uses to navigate.

How two of the big wire-free brands handle it, according to their UK pages:

• Mammotion includes 36 months of 4G data with the Mammotion LUBA 3 AWD, says its network RTK service is free, and makes 4G optional after that.
• Segway Navimow includes 12 months of data on its i2, H2 and X4 mowers and says network RTK access is included; after the first year, a paid renewal keeps remote and anti-theft features working.

What to check for any model:

• Does the mower still mow, and still navigate accurately, if you don't renew the data plan?
• How long is the included period, and what does renewal cost?
• Is tracking part of the free period or an extra module?

Wired mowers and many basic wire-free models have no ongoing costs beyond blades and electricity. Our network RTK and 4G guide covers the subscription question brand by brand.

Nobody publishes a reliable figure. Manufacturers don't state expected lifespans, and there's no independent long-term data covering today's models, so be wary of anyone quoting a precise number of years.

What you can go on:

• The warranty. Standard cover on current models runs from two years to five, and some longer warranties depend on registration or dealer servicing. It's the only firm commitment you'll get about how long the maker expects the mower to hold up.
• The battery. Lithium-ion packs lose capacity as they age, so the mower gets through less lawn per charge over time. Check that the battery can be replaced and that the manufacturer sells spares in the UK.
• Parts and service. Brands with UK dealer networks or parts shops make it easier to fix a mower rather than replace it. Blades, wheels and bumpers are the usual wear parts.
• Software support. Wire-free mowers depend on an app and on regular updates. A mower that stops getting them can still work, but features and compatibility may suffer. Few brands say how long they will support older models.

Looking after the mower helps: clean it regularly, change blades before they're blunt, and store it dry over winter with the battery charged, as most manuals advise. See our winter storage guide and are robot mowers worth it? for how warranty length feeds into the value calculation.

Very little. Robot mower batteries are small, typically well under a third of a kilowatt-hour, so even a mower that charges several times a week uses only a few dozen kilowatt-hours a year, including what the charging station draws on standby.

Our running-costs guide works through an example and arrives at roughly £6 to £10 a year at an assumed 25p per kWh. Your own figure depends on your tariff; Ofgem publishes the current energy price cap. Electricity is the smallest running cost: blades and, in time, a replacement battery cost more. The running-costs calculator adds them together.

Every few weeks to a few months during the mowing season, depending on the lawn and the blade type. Husqvarna's UK support pages suggest every 6–8 weeks for its standard blades and 3–4 months for its longer-life ones, and other brands give similar ranges. Over a UK season that usually means two to five sets a year.

Change them sooner if the grass tips look torn or brown a day after mowing, if the blades are nicked or bent, or if the mower gets noisier. Stony soil, twigs and fallen fruit wear them faster. The blades are cheap and usually screw on, but wear gloves and switch the mower off first. Our blade guide covers types and costs, and the blades page lists replacement packs.

Start by measuring the lawn area, then choose a mower whose rated area is comfortably bigger, around 20% or more above your lawn, rather than one that only just covers it.

The rated area, given in square metres, is the maximum lawn the manufacturer says the mower can keep on top of. It usually assumes ideal conditions: a simple shape, flat ground and the mower running for long hours through the week. Real gardens cut that down. Things that eat into capacity include:

• Several separate zones or a narrow passage the mower has to travel through
• Slopes, which drain the battery faster
• Lots of trees, beds and obstacles to work around
• A daylight-only schedule, which we recommend for wildlife

Buying a size up means the mower can finish in fewer, shorter sessions, which leaves room to avoid evenings and wet days. Buying too small leads to a lawn that never looks quite finished.

To measure, pace out the lawn or trace it on an online map. Our lawn size tool lets you draw the outline on a satellite view and gives the area. Then use the mower finder to shortlist models by area, slope and budget. Rough guide: a typical small terraced-house lawn is under 200 m², a larger suburban garden is often 300 to 800 m², and 1,000 m² or more is a big lawn by UK standards.

Most robot mowers can mow in the dark, but in the UK you shouldn't let them. The main reason is hedgehogs.

Hedgehogs forage on lawns at night, and when threatened they curl up rather than run. Research led by Dr Sophie Lund Rasmussen found that robot mowers can injure them and that the mowers tested needed physical contact to detect one. Hedgehog Street, run by the British Hedgehog Preservation Society and People's Trust for Endangered Species, advises running robot mowers in daylight only. Frogs, toads and other small animals are also most active around dusk and after dark.

Cameras and LiDAR on newer mowers are aimed at obstacles such as toys, shoes and pets. No manufacturer we know of publishes independent evidence that its mower avoids hedgehogs, so a detection claim is not a reason to mow at night.

Two practical points follow:

• Set the schedule for daylight with a margin after sunrise and before dusk, and move it as the evenings draw in. Check that any rain-delay feature can't push a session into the evening.
• Size the mower so it doesn't need the night. If it can only keep up by running round the clock, it is too small for the lawn. A mower with a rated area comfortably above your lawn size will finish in daytime hours.

Daytime mowing is also kinder to neighbours, since some mowers are noticeably loud. Our hedgehog and wildlife guide covers schedules in more detail.

Most people can do it themselves. Wire-free mowers are the easiest: you place the charging station, plug it in, and map the lawn by driving the mower round the edge with your phone. Some models also need an RTK aerial fixed on a pole or wall with a clear view of the sky, which is a simple job but adds a step.

Wired mowers take longer because of the perimeter wire, but it's still a DIY task if you're patient. Some mowers are sold through dealers who offer installation, including Segway Navimow's Segway Navimow H2 Series and some Husqvarna Automower models, and that help is worth having if your garden is large or complicated.

Either way, you need a mains socket within reach of the charging station, ideally protected by an RCD. See our installation guide.

It isn't technically hard, but it's slow and fiddly. You run a thin cable around the edge of the lawn and around any beds or ponds the mower should avoid, keeping to the distances the manual gives from walls and edges, and connect both ends to the charging station.

The wire can be pegged on the surface, where the grass grows over it within a few weeks, or buried a few centimetres down with a spade or a hired cable-laying machine. Burying it protects it from scarifiers and edging tools. For an average garden, allow most of a day, longer if the shape is complicated.

Common snags are a wire cut by a spade or edging tool, and awkward corners where the mower gets stuck. Many dealers install wired mowers for a fee. Our installation guide and our wire vs wire-free guide cover the options.

Not well. Robot mowers are built to maintain a lawn, not to reclaim one. Their small blades and modest motors are meant to take a little off grass that's cut every few days. Long, thick or tufty grass slows them, tangles the disc, drains the battery and leaves a ragged result.

If your lawn is overgrown, cut it first with a conventional mower, in a couple of stages if it's very long, and then let the robot take over. Set the robot's cutting height high for the first week or two and lower it gradually.

If you like a longer lawn, check the maximum cutting height. Many mowers top out at about 60 mm, while some go higher: Mammotion quotes 90 mm for the YUKA and Segway Navimow 95 mm for the Segway Navimow X4 Series.

Mild bumps are fine; holes and ridges are the problem. Robot mowers have small wheels and low bodies, so dips, molehills, exposed roots and ruts can make them stick, scalp the high spots or leave the low spots long.

Before installing one, fill holes with topsoil, level obvious humps, and deal with molehills. Set the cutting height a little higher than you would on a smooth lawn so the disc doesn't scrape the tops of bumps.

Drive type makes a difference on rough ground. All-wheel-drive models, such as Mammotion's LUBA range and Segway Navimow's Segway Navimow i2 AWD, grip better than two-wheel-drive mowers when a wheel loses contact. The spec to look at is the maximum obstacle height the manufacturer quotes, where it publishes one. Mark areas you can't level, such as a bed of tree roots, as no-go zones.

Not the bold stripes you get from a traditional mower. Those come from a roller that bends the grass one way then the other; the RHS notes that you need a mower with a rear roller for them. Robot mowers have no roller.

Wire-free mowers that navigate by RTK, LiDAR or cameras do cut in straight, parallel lines, and some apps let you choose the angle of those lines or change it between sessions. That can leave a faint pattern for a day or so, but it is subtle. Wired mowers that move at random leave no pattern at all.

If stripes matter to you, the usual approach is to let a robot mower keep the lawn short and even through the week and run a roller mower over it before a special occasion.

No. Robot mowers have no grass box. Because they cut little and often, each session takes off only a few millimetres, and the tiny clippings drop down between the grass stems, where they break down quickly and return nutrients to the soil. This is sometimes called mulching.

On a lawn that's mown regularly, you shouldn't see clippings lying on top. You will if the grass is long or wet when the mower runs, which is why it helps to cut an overgrown lawn with a normal mower before handing it to a robot, and to avoid mowing in the rain. The one exception we know of in the UK market was Mammotion's optional sweeper kit for the discontinued Mammotion YUKA.

Only a light scattering. A robot mower chops a few leaves into small pieces along with the grass, which is fine. A thick layer is a different matter: it can clog the cutting disc, hide obstacles and sticks from the sensors, and smother the grass underneath if left in place.

In autumn, rake or blow heavy leaf fall off the lawn before the mower runs, and cut back the schedule as growth slows. The RHS's autumn lawn care advice covers what else the lawn needs at that time of year.

A few mowers have tried to solve the problem. Mammotion offered an optional sweeper kit for the Mammotion YUKA, which collected leaves and clippings, but the YUKA is no longer sold new in the UK. Our winter guide covers when to stop mowing for the year.

Rarely all the way. Most robot mowers have a single cutting disc set in the middle of the body, so there's a strip between the blades and the outside of the mower. Where the lawn meets a wall, fence or flower bed, that leaves a band of uncut grass to trim with shears or a strimmer.

How wide the strip is depends on the design and the edge:

• Flush edges such as paving laid level with the lawn are the easy case. Many mowers, wired and wire-free, can run with one wheel on the paving so the disc reaches the edge of the grass.
• Walls, fences and raised beds are harder, because the mower can't overlap them.
• Edge-focused designs get closer. Mammotion fits a separate edge disc to the Mammotion LUBA mini 2 AWD and claims about 5 cm from walls; Segway Navimow claims a similar distance for the Segway Navimow H2 Series and Segway Navimow X4 Series. These are manufacturer claims, and a fixed-height edge disc may leave a slightly different finish from the main cut.

A popular fix is a mowing strip: a row of bricks or slabs laid flush along beds and walls so the mower can ride along it. It also stops the edge being churned by wheels. The RHS has advice on maintaining lawn edges if you want to keep them crisp by hand.

When you compare models, look for an edge-cutting mode and any published distance to the edge, and treat a "zero edge" claim with caution unless the manufacturer explains what it means.

No. A robot mower cuts grass; it doesn't rake, scarify or treat moss. Moss is a sign of the conditions in the lawn rather than of how it's mown. The RHS notes that moss often thrives in shady, damp areas, and its guide to moss in lawns explains when it's worth tackling at all.

Regular, light cutting can help grass stay dense, which leaves less room for moss, but that only works if the grass has enough light and drainage to grow. Mowing very short tends to weaken grass, so don't set the cutting height at the minimum on a mossy lawn.

Mossy, wet patches can also cause the mower problems: wheels lose grip, especially on slopes, and may leave marks. If you scarify, do it with the mower paused, and clear the debris before it runs again.

More often than you'd mow by hand. Robot mowers are designed to trim a little at a time, so most owners schedule them several times a week in the main growing season, from roughly late spring to late summer, and cut back in spring and autumn when growth slows.

A few rules of thumb:

• Start with the schedule the app suggests for your lawn size, then adjust. If clippings are visible or the lawn looks shaggy, add sessions; if it looks scalped or the ground is getting marked, drop some.
• Keep sessions to daylight hours for wildlife and neighbours.
• Give the lawn a rest in drought and when it's waterlogged.

If the mower has to run almost every day for most of the day to keep up, it's undersized for the garden. The lawn size tool helps you check.

Often, yes. How well it works depends on how the two lawns are connected and what kind of mower you choose.

If there's a path between them, such as a side passage, most wire-free mowers can drive from one lawn to the other along a route you draw in the app, and mow them as separate zones. The key spec is the minimum passage width. Mammotion says the Mammotion YUKA mini 2 fits through 55 cm gaps, and Segway Navimow gives 70 cm for the Segway Navimow H2 Series, while the older Segway Navimow i Series (i1) asks for 100 cm. Measure your narrowest point, including gates, before you buy. Wired mowers can do the same with the wire run through the passage, plus a guide wire to help them find their way back.

If the lawns aren't connected, or the only route is across a road or steep steps, you'll need to carry the mower between them. Many wire-free mowers can store several maps, so you place it on the other lawn and start that map. Weight matters here: compact models weigh around 10 to 12 kg, while big all-wheel-drive machines can weigh nearly 30 kg.

Also think about the front lawn's security. A mower working unattended by the street is more exposed, so a PIN, alarm and GPS tracking are worth having. Our complex gardens guide covers passages, zones and multiple lawns in more detail.

Not usually. Very few mowers need your home Wi-Fi to cut the grass, but many need some kind of connection for setup and for the extras.

Wired mowers (the ones that follow a perimeter wire) often work with no connection at all. Many have a keypad or buttons for setting a schedule, and the app, if there is one, is an optional extra.

Wire-free mowers almost always need a phone app, because the app is how you map the lawn. During mapping your phone talks to the mower over Bluetooth or Wi-Fi. After that, how much connectivity matters depends on the navigation:

• Network RTK mowers get their satellite corrections over the internet, normally through a built-in 4G connection rather than Wi-Fi. They need decent mobile coverage at the lawn, not a strong router signal.
• LiDAR and camera mowers work out their position on board, so they don't need a connection to navigate.
• Mowers with their own RTK aerial get corrections from that aerial locally.

Wi-Fi is mainly useful for controlling the mower from the house, receiving software updates and getting alerts. At the bottom of a long garden it may not reach, which is one reason built-in 4G has become common on wire-free models.

Our guide to network RTK and 4G explains how to check coverage before you buy.

It depends on how the mower finds its position. Trees are the classic weak spot for satellite-based navigation, and much less of a problem for LiDAR, cameras or a wire.

RTK mowers work out where they are from satellite signals, corrected to centimetre accuracy. They need a reasonably clear view of the sky. Dense tree canopy, tall hedges and nearby buildings block or reflect signals, so accuracy can drop in those spots, and the mower may pause, slow down or leave strips uncut until it recovers.

LiDAR and camera mowers measure their surroundings instead. Trees, walls and fences are useful landmarks for them, so they tend to cope well in enclosed, leafy gardens. Their weak spot is the opposite: large open areas with little around them to measure against.

Hybrid mowers combine the two, using RTK in the open and LiDAR or cameras under cover. Segway Navimow's Segway Navimow i2 LiDAR Pro and Segway Navimow H2 Series, and Mammotion's Mammotion LUBA 3 AWD (3000 and 5000 versions), all work this way.

Wired mowers follow a cable, so trees don't affect their navigation at all, though roots and low branches can still cause them to get stuck.

If your lawn is heavily shaded, favour LiDAR or a hybrid, or a wired mower. Our RTK vs vision vs LiDAR guide goes through the trade-offs, with a diagram of how trees affect satellite signals.

It stops the blades, tries to free itself, and if that fails it stops and waits for you. Connected mowers send an alert to your phone; basic models show an error on the display or flash a light.

The usual causes are predictable: a wheel dropping into a hole or rut, soft ground after rain, exposed roots, a low branch or garden furniture, wet slopes, and on wire-free mowers a patch where satellite or LiDAR positioning drops out. Each time it happens, fix the cause rather than just rescuing the mower. Fill the hole, add a no-go zone, raise the branch or move the furniture. Most gardens settle down after the first few weeks.

It shouldn't, as long as the boundary is set up properly, but no mower is designed to spot a drop or water by itself reliably, so the boundary is what protects it.

Wired mowers stay inside the perimeter wire. Manufacturers' installation instructions give minimum distances to lay the wire from ponds, drops and walls, and following them is what keeps the mower on the lawn. Many also recommend a physical barrier around a pond.

Wire-free mowers stay inside the boundary you draw in the app. RTK mowers are accurate to a few centimetres in open ground, but accuracy can wander near trees and buildings, and cameras and LiDAR are good at seeing walls and objects, not necessarily the edge of a sunken pond or retaining wall. Draw the map with a margin from any hazard, mark ponds and flower beds as no-go zones, and watch the first few runs.

Watch for three things in particular:

• Lawns that end at a drop such as a retaining wall or steps. Leave a buffer, or fit edging or a low fence.
• Slopes that run down to water. Wet grass can let a mower slide past where it meant to stop.
• Boundary slope limits. Some manufacturers set a lower slope limit at the edge of the map than on the lawn itself. Segway Navimow's manual for the i Series limits boundary slopes to 10%, for example.

For layout advice, see our guide to installing a robot mower.

Much quieter than a petrol or corded mower, but not silent, and some are clearly louder than others. Most figures quoted by manufacturers fall between the mid-50s and about 70 dB(A). As a rough guide, the low end is a gentle hum you'll barely notice indoors, and the top end is closer to a vacuum cleaner in the next room.

Some examples from manufacturers' own figures:

• Segway Navimow's original Segway Navimow H Series (H1): 54 dB(A)
• Navimow's Segway Navimow i2 LiDAR: 59 dB(A)
• Navimow's Segway Navimow X4 Series: 68 dB(A)
• Mammotion's Mammotion LUBA 3 AWD: 70 dB(A)

Be careful comparing them, because brands measure differently. Some publish a declared sound power level to the European mower standard, which includes an uncertainty margin. Others quote a lab figure taken with the blades not cutting, which flatters the result. Navimow's footnotes say its i2, H2 and X4 figures are measured without cutting load. Several brands publish no figure at all, including Mammotion for the LUBA 2 AWD.

The decibel scale is logarithmic, so a 70 dB(A) mower is far louder than a 57 dB(A) one, not just a bit. Bigger mowers with wide decks and all-wheel drive tend to be at the loud end. If you want to mow while you're in the garden, or your neighbours are close, favour a quieter model and a daytime schedule.

Most can, but you usually won't want them to. Robot mowers are built to live outside, and manufacturers give them water-resistance ratings such as IPX5, IPX6 or IP66, so a shower won't harm one. The question is what rain does to the lawn and to the cut.

Wet grass clumps and tears rather than slicing cleanly, clippings stick to the underside of the deck, and soft ground shows wheel tracks, especially along the route back to the charging station. Wet grass is also slippery, so a mower that copes with a slope when it's dry may slide or spin on the same bank after rain.

There are three common ways mowers deal with this:

• A rain sensor that sends the mower home when it detects water, then waits before trying again. Segway Navimow lists one on the Segway Navimow X4 Series and Segway Navimow H2 Series, for example.
• Weather-forecast scheduling in the app, which skips planned sessions when rain is due. Navimow's i2 range relies on this rather than a sensor.
• Nothing automatic, leaving you to pause the schedule yourself.

If rain behaviour matters to you, check the spec sheet for a rain sensor and whether you can set a delay after rain. Rain doesn't affect satellite RTK positioning in any meaningful way, so wire-free mowers navigate as normal. For more on wet-weather care and when to stop for the season, see our winter storage and maintenance guide.

They're designed to be much safer than a conventional mower, but they are still machines with sharp blades, and every manual says not to leave children or pets unsupervised near one while it's running.

The safety features are fairly standard across the market:

• Small blades under the body. Most mowers use small pivoting razor blades on a disc set well inside the shell, and the blades fold back if they hit something hard.
• Lift and tilt sensors that stop the blades within a moment if the mower is picked up or tipped.
• Bump sensors that stop or turn the mower on contact.
• A PIN or child lock so it can't be started by pressing buttons.
• Obstacle detection by camera, LiDAR or ultrasonic sensors on many newer models, which aims to steer round objects before touching them.

The weak points are small hands and paws reaching under the edge of a moving mower, and small animals that don't move out of the way. Obstacle detection claims are the manufacturer's and refer to objects such as toys, shoes and pets; they aren't a guarantee.

The simplest safeguard is the schedule. Set the mower to run when the garden isn't being used, such as weekday mornings while the children are at school, and pause it from the app when they're playing outside. Teach children that the mower isn't a toy, and pick up toys and dog balls before a session. For wildlife, keep to daylight hours; see our hedgehog guide.

It varies a lot, from about 25% on basic models to over 80% on the latest all-wheel-drive machines. The figures are percentages, not degrees, which causes confusion: a 100% slope is 45 degrees, 45% is about 24 degrees and 80% is about 39 degrees.

Typical ranges:

• Two-wheel-drive mowers are commonly rated from about 30% to 50%. The older Segway Navimow i Series (i1) is rated for 30%.
• All-wheel-drive mowers go much further. Mammotion rates the Mammotion LUBA 3 AWD for 80% and Segway Navimow rates the Segway Navimow X4 Series for 84%.

Read the small print. Ratings are maximums, often measured on dry grass, and Navimow's footnote for the X4 says its test was under manual remote control. Some manuals also set a lower limit at the edge of the map than on the open lawn. Wet grass, moss and soft ground all reduce grip.

To measure your own slope, put a straight plank on the steepest part, hold it level, and measure the vertical gap to the ground at the far end. Divide the gap by the plank length and multiply by 100. Choose a mower rated comfortably above the steepest section you want cut. Our slopes guide explains the maths and how drive type affects grip.

They can be. A robot mower is valuable, portable and left outside on its own for hours, so it's an obvious target, particularly on a front lawn. There's no reliable UK theft data for robot mowers specifically, but the risk is real enough that most manufacturers now build in several layers of protection.

What to look for:

• A PIN code so a stolen mower can't be used or reset without it. This is standard on most models.
• A lift or tamper alarm that sounds if the mower is picked up.
• GPS tracking over 4G, so you can see where it is in the app. This needs an active data connection, and on many mowers the data is free for a period and then a paid add-on.
• Geofence alerts that warn you if the mower leaves its map.

Practical steps help too. Register the serial number with the manufacturer and with Immobilise, keep the mower in the back garden or a lockable space when you're away, and avoid scheduling it on a front lawn when nobody's home. Check that your home insurance covers a mower left in the garden, as some policies limit cover for items outdoors.

Tracking helps recover a mower, but it doesn't stop a determined thief. Our theft and security guide explains each feature and its limits.

No. Robot mowers are built to sit outside on their charging station through the mowing season, and they carry water-resistance ratings for that reason. A garage is an optional extra, and most mowers don't include one.

A garage or canopy can help in a few ways: it keeps direct sun off the mower on hot days, keeps leaves and bird droppings off the charging contacts, and some people like the look. The downsides are cost, a bigger footprint by the dock, and the risk of getting in the way. A roof over a wire-free mower must not block the RTK aerial's view of the sky, the LiDAR or the cameras, and the mower must still be able to dock squarely.

Our guide do you need a robot mower garage? covers what to look for, and the garages and houses page lists options.

Yes, for most UK gardens. Once the grass stops growing, usually some time between late October and November, there's little for the mower to do, and frost, waterlogged ground and months of wet weather do it no favours. Most manufacturers recommend storing the mower indoors for the winter.

A typical end-of-season routine looks like this:

• Clean it. Brush dried grass off the underside and wheels, and wipe the body. Don't hose it unless the manual says that's allowed.
• Check the blades and replace them now or in spring.
• Charge the battery to the level the manual recommends, then switch the mower off.
• Store it somewhere dry and frost-free, such as a garage or shed that doesn't freeze. Lithium-ion batteries dislike both freezing and heat.
• Deal with the dock. Many manuals suggest bringing the charging station and power supply in too. A perimeter wire can stay in the ground. An RTK aerial can usually stay up, but check the manual.

Some owners keep mowing on mild winter days, and a few mowers have frost sensors that stop them starting in the cold. If you do, cut the schedule right back and avoid frozen or saturated grass, which marks easily.

In spring, recharge, update the software, check the map still fits the lawn, and restart with a higher cutting height for the first few sessions. Our winter storage guide has the full checklist.