Lawnmowers

Performance: Petrol mowers with decent-sized engines (160cc+) develop more torque (rotational force) at max blade speeds than electric models. This means in dense, long grass, a good petrol mower is less likely to slow or stall.

While we don’t recommend mowing grass when it’s wet, petrol mowers are better than battery models at packing the catcher if the turf’s damp.

Mulching: Most petrol mowers, even budget models, can mulch. This means they come with a plug you chuck in the catcher chute to recirculate clippings through the blades, turning them into a fine mulch.

Modern petrol mowers have dual-purpose blades (catch and mulch), meaning you only have to add the plug to convert between modes.

Ease of use: Petrol mowers are harder to use than electric models. Most still have a pull cord start, which can take a few yanks to get going when it’s cold. They’re also much louder and produce fumes (though modern 4-stroke models are quieter and run much cleaner than old 2-strokes, and you don’t need to mix petrol and oil). Petrol models are heavier and more difficult to manoeuvre than electric models.

Price: You can buy one of our recommended petrol mowers for less than $500, though you’ll pay at least $900 for a self-propelled model.

Cutting height range: Petrol mowers generally offer the widest range of cutting heights, from 10/15mm up to 80/100mm. Be aware some mowers manufactured overseas, such as the American-made Toro, only cut down to 25mm. Kiwi or Aussie mowers such as Masports, Victas and LawnMasters let you get as low as 5mm or 10mm.

Running time: A big drawcard of petrol mowers remains their infinite running time as long as you’ve got fuel in the tank.

Reliability: The four-stroke engines powering petrol lawnmowers operate at high temperatures and can have the same mechanical issues as cars. They require regular maintenance and servicing, including spark plug and oil changes. However, modern petrol mowers are relatively reliable. Our latest appliance reliability survey found 83% of petrol mowers owned by members had never needed repair.

Performance: Battery-electric mowers produce less torque than petrol models, but our recommended models are more than powerful enough to give most lawns a clean, even finish – and they have sufficient power to tackle the longish grass that develops after you’ve let your lawn go for a few weeks. You’ll only notice the power disparity compared to petrol in grass that’s damp or very long (for example, 200mm-plus), or when thatching and weeds are in the mix.

Mulching: A couple of years ago, no battery-electric mowers offered a mulching mode – it was cut or catch only. Now, most of our recommended battery mowers are mulch-and-catch. And their performance in mulching mode is often as good as their petrol counterparts, meaning they cut the clippings as finely and spread the mulch as evenly. The snag is a mulching battery-electric mower costs double that of some of our recommended petrol mowers.

Ease of use: Most battery-electric mowers are 10kg to 15kg lighter than their petrol equivalents, making them much easier to haul out and shove around. They’re also quieter, have lower levels of vibration, and start at the push of a button. However, the most powerful battery mowers weigh in excess of 20kg, making them not much lighter than many petrol mowers.

Price: One of our top-scoring battery-electric mowers will set you back at least $800. With a battery mower, you’re essentially paying your running costs upfront. You avoid paying $50 to $100 in petrol each summer (they cost about 10¢ to recharge at most), and there’s little in the way of maintenance. A bonus is all cordless mowers are part of a family of outdoor power gear, meaning their batteries will work in blowers and line trimmers etc., saving you money on your next tool as you only need to buy the “skin” (tool excluding battery and charger).

Cutting height range: Cordless mowers don’t generally cut as low as petrol models, only getting down to about 20mm, although Australian battery mowers such as the EGO or Victa go down to 15mm – the lowest battery cutting heights we’ve seen for cordless.

Running time: The major limiting factor for cordless models is that even the best only have about 35 minutes’ mowing before needing to recharge for more than an hour. This equates to about 200-300m2 of turf if you’re working quickly, so if your lawn is bigger than this you’ll need to break your mowing in two or pay another couple of hundred dollars for an extra battery. However, some retailers are starting to include two batteries in their cordless mower kits.

Reliability: Battery-electric mowers have fewer moving parts than petrol mowers, so they’re more reliable: 84% of our members with a battery mower said it had never needed repair. Of those that had, the majority of failures were batteries conking out. This isn’t surprising as batteries gradually lose capacity and need replacing after three to five years of regular use. Aside from blade-sharpening, this is the only major ongoing cost associated with these mowers.

Performance: Mains-electric models are less powerful than either petrol or battery units, as they’re limited by the amount of current they can draw from a wall socket. This means they give a more ragged cut than other mowers, and struggle when the going gets tough. However, for small patches of turf within reach of an extension cord, their low cost ($300, compared to double that for a petrol or battery mower) can make them worth considering.

Mulching: Mains-electric mowers are generally cut or catch only (“cut” means mowing without a catcher or mulching plug, so thick clumps of grass are returned to the lawn surface). However, some mains models, such as the Flymo Turbo Lite hover mowers, cut quite finely on the first pass and recirculate some of the clippings through the blades, offering a pseudo-mulching effect.

Ease of use: Corded mowers are the lightest of the lot. They’re also quiet and easy to start. However, dragging a power cord can be a hassle. Always use an RCD (residual current device) plug to avoid a shock if you cut the cord.

Price: Corded mowers are also the cheapest type aside from hand mowers; you can land a decent model for just $300 as they’re simple beasts with no expensive battery, charger or engine.

Cutting height range: Generally, mains-electric mowers don’t cut as low as petrol models, though Flymo hover mowers go down to 10mm (but they won’t give you as fine or even a cut at this height as a petrol mower).

Running time: Mains-electric mowers theoretically have no run-time limit, though you’re limited by the extension cord and they’re not designed for big jobs so can overheat if used for long periods.

Reliability: With no batteries and very few moving parts, it’s unsurprising mains-electric mowers are the most reliable type.

Mulching mowers have a specially shaped cutting blade and a catcher-chute plug.

With the catcher removed and the plug inserted, the clippings are spun under the body and chopped up further by the blade. They are then blown down into the lawn, leaving a smoothly mown surface.

For successful mulching, the grass can’t be too short or too long. Cut too short and there won’t be a carpet of grass for the mulch to sink into and decompose. Left too long after cutting and the mulch will form clumps on the lawn – especially if the grass is wet. As well, the length of the cut shouldn’t be more than 25mm.

Mulch-and-catch mowers are the most versatile. With the catcher attached and mulching plug removed, they can be used as a conventional catcher-only mower. Mulcher-only mowers dispense with the catcher. They operate in mulching mode only.

We test lawnmowers on a large turf farm in early spring, which allows us to compare each mower on the same type of grass at a consistent length. Our overall scores comprise performance (50%) and ease of use (50%).

Performance scores are based on the following:

• Cutting short (30mm) grass to 15mm
  
• Cutting medium-length (approx. 75-100mm) grass to 30mm
  
• Cutting long (approx. 300-400mm) grass on the highest cut setting
  

We run the short and medium-length grass tests with the mower in both catcher and mulching modes where applicable. Neither the catcher nor the mulcher is used for the long grass test.

High performance scores are awarded for a clean and even lawn surface with a uniform grass height. Penalties apply for any uncut grass or grass left in clumps. Points are also deducted when mulching mowers fail to blow the small clippings back evenly onto the lawn, or where the engine slows or stalls while cutting.

Ease of use is assessed on:

• Vibration (20%)
  
• Pushing/manoeuvring (20%)
  
• Handle comfort (20%)
  
• Controls (10%)
  
• Cutting height adjustment (10%)
  
• Catcher convenience (10%)
  
• Ease of starting (10%)
  

• Body: A rotary mower’s body is made from steel, aluminium alloy or (less commonly) plastic. An alloy body is more expensive. It’s corrosion resistant and likely to last longer in damp conditions – although it won’t last as well in sandy coastal areas because sand wears away the aluminium. Steel is cheaper but will rust unless cleaned and dried after use. However, if hit by a large rock it’ll only dent – whereas an alloy body can crack. Plastic is lightweight and doesn't corrode … but it may not last as well if regularly pounded by stones and other debris. A plastic body is more suitable for well-tended lawns where there’s only a slight chance of it being hit by rocks or stones.
• Handle: A turned-up handle is generally regarded as easiest to use. Adjustable height is also an advantage, although it's not as common as you might think. The handles should fold easily for stowing.
• Throttle control: Located on the handle bar for quick and easy access. It shouldn't be stiff.
• Cutting height: Look for a large number of cutting positions. It should be easy to change the position using 1 lever acting on all 4 wheels.
• Catcher: Catchers can be either solid plastic or partly mesh. Rigid plastic is heavier, but stronger than the mesh type, which can allow dust to blow over the user. The catcher should have 2 handles, 1 for carrying and the other for emptying. It should be easy to remove and replace.
• Engine maintenance: How easy will it be to change the oil, air filter and spark plug?
• Starter cord: Some mowers have the starter cord on the handle, so you use just your arm and perhaps upper body to operate it. Others have the cord down on the engine casing, requiring a full body pull. Neither guarantees an easy start, and both have their fans. If you're not familiar with either style, ask to try it in the shop. Some cords are located on the upper handle, which restricts the pulling action more than those placed further down the handle. Left-handers may find it harder to use a starter cord on the handle.
• Wash port: Look for a hole on top of the body, designed for you to connect a hose to, for easy cleaning underneath.
• Noise: There's no such thing as a quiet petrol-driven mower, but some are noisier than others. Check the vibration as well.
• Easy push: Ball-bearing wheels make pushing easier.

• The body of the mower should come close to the ground so that it's not possible for your foot to touch the blades.
• The mower should stop quickly when the engine is turned off.
• Check blade/s and blade bolts visually for looseness or wear before mowing.
• Don't persevere with a blunt blade. Have it sharpened.
• Wear strong, heavy non-skid footwear. Never mow in bare feet.
• Use ear and eye protection.
• For mains-powered models, use just one extension cord and make sure the lead is plugged into a residual-current-protected power point or a plug-in residual-current device (RCD).
• Mow along slopes, not up or down them.
• Keep children and pets clear of the mowing area.
• Stop the motor before filling the fuel tank.
• Clean the mower after use. Disconnect the mains or remove the battery before you do anything underneath an electric mower.
• Always disconnect the spark plug before carrying out maintenance on petrol mowers.

• A push mower is the most eco-friendly way of mowing your lawn. But it's only suitable for relatively small, flattish lawns.
• Mains-powered mowers are ideal for smaller sections where there are not too many cord-trapping obstacles in the mowing area.
• Battery models don't have the hassle of a mains lead – but they have a limited cutting time, are heavy, and you have to remember to charge the battery before mowing.
• In our conditions steel-bodied power mowers are cheaper than alloy, but they corrode. Alloy-bodied models are likely to last longer.
• A bigger engine doesn’t necessarily mean better performance – a number of 140cc to 160cc petrol mowers we’ve tested give a cleaner cut than more powerful 190cc models. Similarly for battery mowers, we found motor power/voltage isn’t the best indicator of high cutting scores.

• Generally, don’t cut your grass lower than 2.5cm. This is to avoid “scalping” your lawn, which leads to brown, weak grass and allows weeds to take hold. In cooler months, it’s a good idea to raise your cutting height a little.
• Keep your blades sharp – take the mower back to the dealer to get the blades sharpened if you’re unsure. Dull blades give a ragged cut and tear grass out at the roots, damaging your turf.
• During summer you should mow your lawn at least once a fortnight (ideally once a week if the grass is growing quickly), reducing this frequency to every three or four weeks in winter.
• Alternating your mowing pattern each time you cut your lawn promotes upright, even growth.
• If possible, mow when the grass is dry so the blades are upright and less likely to clump.
• Consider raising the cutting height a little in shaded areas of the lawn, to prevent the growth of weeds.
  
• Try to look 3 metres ahead of you when operating a push mower; this helps you cut straight and true.
• MBIE recommends hearing protection for anything over 85dBA – which is most petrol mowers in our test (we recommend hearing protection when using any petrol mower). Wear eye protection, long pants and sturdy shoes when operating any type of mower. Push the mower across slopes, rather than up or down, to avoid losing control.

Here are some tips to keep your lawn looking its best, come rain or shine.

• In dry spells, set your mower to cut a notch or two higher to avoid scalping your lawn and discourage weeds. It’s also a good idea to leave your catcher off and use your lawnmower’s mulching plug (if it’s got one), as mulched clippings are great for the health of your lawn.

• Give your lawn a deep watering once a week – if water restrictions permit. The best time to water is early morning when it’s not too windy or hot, so it won’t evaporate before it can soak in.

• For lawns with clay soil, it’s best to lightly water over a long period, as they take a while to absorb moisture. Sandy soils quickly drain, so need more frequent but shorter watering periods.

• If water doesn’t easily drain and your lawn has a thatch of spongy, fibrous-looking grass, then the soil is probably compacted and could use aeration. To achieve this, get a garden fork and make holes of about 7.5cm to 10cm every 15cm or so – if this sounds a bit tedious you could buy or rent an aerating machine. Ensure the soil is damp when you aerate.