The only energy needed to move these old-school grass cutters is yours. You push to turn a series of curved blades—it's that simple. Making these perfect for environmentally-conscious home owners. Note: We haven't tested these in a while, so—for now—you won't currently find ratings.

Pros: These mowers don't pollute, and you don't need to store gas, plug in a power cord, or charge a battery (usually—see below). They're quiet, inexpensive, and relatively safe. And you'll get a workout unless you opt for a model that uses a battery-powered motor to spin the blades while you push.

Cons: Most can't trim closer than 3 inches around obstacles. Cutting swaths are typically small at 14 to 18 inches wide. These super-green mowers don't disburse clippings like a rotary version, so you'll need a bag (or a rake) if you're fussy. And be prepared for some strenuous pushing if you let your lawn grow too high.

Upkeep: A manual-reel mower will need an occasional blade adjustment and sharpening.

Best for: Flat yards up to 1/8 acre. 

A step up from a simple push mower, these models draw energy from the engine (or motor on electric models) to power the wheels, which makes them a better bet if you have a larger lawn or live on a sloped lot. All wheel drive offers the best traction on slopes, followed by rear wheel drive. Front wheel drive, which is standard on most models, is still well suited for flat parcels. 

Pros: Most gas self-propelled mowers cut a 21- or 22-inch swath, can handle long or thick grass and weeds, and can bag, side-discharge, and mulch clippings. Electrics start with the push of a button and produce no emissions.

Cons: All wheel drive models can be tough to navigate with the motor off, because their wheels are connected to the transmission. Gas self-propelled mowers are noisy and produce emissions. Electric self propelled models solve those problems but will use up to 20 percent of the battery charge to power the wheels, so you won't be able to cut as much grass unless you buy a larger, or second battery. 

Upkeep: Gas engines require regular tune-ups and oil changes. Electrics require little upkeep beyond blade sharpening.

Best for: Flat yards from 1/4-1/2 acre or sloped yards up to 1/4 acre. 

Push mowers are what most of us imagine when we think of a lawn mower. An engine or motor powers the blade, and you push the mower forward. In our latest tests, the best electric models (powered by lithium-ion batteries) match gas for cutting performance, and get rid of the need for gas, oil, and engine maintenance. Plus they're much quieter. But they're pricey and the batteries have a limited charge. Plug-in electric models solve this problem but don't cut nearly as well.

Pros: Most gas push mowers cut a 21- or 22-inch swath, can handle long or thick grass and weeds, and can bag, side-discharge, and mulch clippings. Electrics start with push-button ease and produce no exhaust emissions. Most offer a rear bag and a mulching mode that cuts clippings finely enough that they settle in and fertilize the grass as they decompose. 

Cons: Gas push mowers are noisy (so use ear protection) and produce emissions. Electrics have a limited runtime—usually enough to cut 1/3-acre. And they're pricier than gas models, though you'll recoup that cost over time.

Upkeep: For gas, plan for regular tune-ups and oil changes. Electrics needs only occasional blade sharpening.

Best for: Yards up to 1/4 acre. 

These gas-powered machines can cut 2 to 3 times faster than simple push mowers, making them best suited for larger lawns. They offer better traction on hills than ZTRs and in the past have provided a more even cut. Models with hydrostatic transmissions are best suited for plows and other tool attachments. 

Pros: Most models mow a 42- to 48-inch swath (though wide deck models cut 54 inches or more in a single pass) and can bag, mulch, and side-discharge clippings. Steering them is easy and familiar, since they use a wheel, just like a car. The best models have comfy, high-backed seats and make it easy to engage the blades and adjust your cutting height. 

Cons: Bagging kits are extra and tend to be expensive—a major reason the majority of tractor owners mow in side-discharge mode. And even today's cleaner machines create exhaust emissions and require lots of storage space. And tractors have a wider turning radius and lower top speed than zero turn radius mowers. 

Upkeep: Gas engines require regular tune-ups and oil changes.

Best for: Yards larger than 1/2 acre. 

Think of these like souped up tractors. Rather than a wheel, you control a zero-turn with a pair of levers—pushing one forward causes the mower to turn in place. They also have nimble handling and higher top speeds than tractors. All but one model in our ratings are gas-powered, and the best now cut as well as lawn tractors. 

Pros: These are similar to the mowers landscapers use, with a rear engine and rear-wheel steering. Maneuverability is excellent around obstacles like trees and flower beds. Some new models have steering wheels. They can side-discharge, bag, and mulch clippings and typically mow a 42- to 50-inch swath. Their nimble handling and high top speed makes it easy to get across your property quickly. 

Cons: Costing more than most tractors, not all models cut as well as tractors. Rear-steering wheels can tear up grass during turns. They can lose traction and be hard to control on hills, and their lever controls require practice. And higher top speed won't save you time when cutting—you'll still want to go at 3 1/2-4 miles per hour to get an even mow. Bagging kits can be pricey.

Upkeep: Gas engines require tune-ups and oil changes. Electrics need at least blade sharpening.

Best for: Yards over 1/2 acre without too many hills. 

Bridging the gap between walk-behind and push mowers, rear-engine riders are typically cheaper than tractors but don't cut as well, or as quickly, because they have narrower decks, typically around 30 inches wide. 

Pros: If the usual lawn-tractor behemoth requires more storage space than you have, this rider is more compact. It's also cheaperœ—some start at $1,000, a few hundred dollars more than the best self-propelled mowers. 

Cons: Even the top-scoring models won't cut as well as some of the lowest-scoring tractors in our ratings. They also usually cut in 30-inch wide swaths, more than a walk-behind mower for sure, but far less than the four feet many lawn tractors will mow. Many have a jerky gear drive, rather than the smooth hydrostatic drive on most tractors. We also found that those in our tests weren’t great at dispersing clippings or fully filling a bag. You also may not get higher-end features like a high-back seat or a fuel gauge you can check while seated.

Upkeep: Gas engines require regular tune-ups and oil changes. Electrics need annual blade sharpenings.   

Best for: Yards 1/2-1 acre. 

Robotic mowers buzz along within a wired perimeter.

Pros: These mow-bots are designed to crisscross randomly, reversing direction when they reach the wire or an obstacle, and return to a charge station when necessary. You can set a schedule and the mower will start on its own—although we recommend someone keep an eye on it. Another plus: They produce no emissions.

Cons: You need to set up a perimeter wire to delineate the mowing boundaries. Performance varies widely and cut quality is often less than a conventional mower's, and they're expensive. 

Upkeep: Regular blade sharpening and cleaning underneath.  

Best for: Yards up to 1/4 acre—provided you have someone at home who loves tech and is willing to set up and monitor the mower.