Greenworks 21″ Self-Propelled Lawn Mower 5.0Ah Review: The Quiet Revolution with a Catch

I remember those Saturday mornings vividly. The sun would just be cresting the horizon, birds chirping, a fresh cup of coffee in hand… and the impending dread of wrestling with my old gas mower. The endless yanking on the pull-cord, the sputtering engine, the cloud of blue smoke, and the deafening roar that shattered the neighborhood peace. It was a weekly ritual of frustration, not to mention the messy oil changes and last-minute runs to the gas station. We’ve all been there, feeling that lawn care shouldn’t be a workout before the actual work even begins. The dream has always been a simpler solution: a mower that starts with the push of a button, runs quietly, and gets the job done without the fumes and fuss. This desire for a more civilized, less strenuous approach to maintaining a beautiful lawn is precisely why battery-powered mowers have surged in popularity, promising to turn a chore into a more pleasant, almost therapeutic experience.

What to Consider Before Buying a Walk-Behind Lawn Mower

A Walk-Behind Lawn Mower is more than just an item; it’s a key solution for maintaining the health and appearance of your property. It’s your primary tool in the fight against unruly grass, weeds, and the slow creep of suburban wilderness. The main benefits of a quality mower are a clean, uniform cut that promotes healthy grass growth, the versatility to handle different conditions through mulching or bagging, and, increasingly, a user experience that minimizes physical strain and environmental impact. A good mower doesn’t just cut grass; it empowers you to take pride in your outdoor space with efficiency and ease. It transforms a laborious task into a manageable, even enjoyable, part of your home maintenance routine.

The ideal customer for a battery-powered, self-propelled model like the Greenworks 21″ Self-Propelled Lawn Mower 5.0Ah is a homeowner with a small to medium-sized lawn, typically up to half an acre, who values convenience, quiet operation, and low maintenance above all else. This includes those with sloped or uneven terrain where the self-propel feature can be a real back-saver. It’s perfect for people living in neighborhoods with noise restrictions or those who simply prefer not to disturb their family or neighbors. Conversely, this type of product might not be suitable for those with exceptionally large properties (over an acre) where the limitations of battery runtime would require multiple batteries and lengthy recharge cycles. For them, a gas-powered riding mower might be a more practical, albeit louder and higher-maintenance, alternative.

Before investing, consider these crucial points in detail:

• Deck Size & Material: The cutting width, or deck size, determines how many passes you’ll need to make. A 21-inch deck, like the one on this Greenworks model, is a fantastic sweet spot for balancing maneuverability with efficiency on lawns up to half an acre. The deck material is equally critical; a steel deck provides superior durability and rigidity compared to plastic, ensuring it can handle the occasional bump or stray obstacle without cracking.
• Power Source & Runtime: The heart of a cordless mower is its battery system. Voltage (V) and Amp-hours (Ah) are the key metrics. Voltage indicates power, while Amp-hours relate to runtime. A 40V system with a 5.0Ah battery is robust, but real-world runtime is heavily influenced by grass thickness, moisture content, and usage of features like self-propel. Always be realistic about manufacturer claims and consider if your yard size might necessitate a second battery.
• Propulsion: Self-Propelled vs. Push: A push mower is simple and lighter, but a self-propelled model can be a game-changer, especially on hills or for users who want to minimize physical exertion. Rear-wheel drive, as featured here, generally offers better traction and control than front-wheel drive, particularly when the collection bag is full or when navigating inclines.
• Ease of Use & Storage: Look for features that simplify operation. A single-lever height adjustment is far superior to changing each wheel individually. Push-button start is a non-negotiable benefit of electric models. Finally, consider storage. Many modern battery mowers, including this one, feature a vertical storage design, which dramatically reduces the footprint in a crowded garage or shed.

While the Greenworks 21″ Self-Propelled Lawn Mower 5.0Ah is an excellent choice, it’s always wise to see how it stacks up against the competition. For a broader look at all the top models, we highly recommend checking out our complete, in-depth guide:

First Impressions: Solid Build, Simple Setup, and One Glaring Inaccuracy

Unboxing the Greenworks 21″ Self-Propelled Lawn Mower 5.0Ah was a refreshingly simple affair. Confirming reports from other users, the assembly process is practically nonexistent. You simply unfold the handle, lock it into place with the easy-to-use clamps, and you’re essentially ready to go. The battery and charger are packed separately and feel substantial. My initial impression of the mower itself was one of robustness. The 21-inch deck is made of solid steel, not flimsy plastic, which inspires confidence in its longevity. The wheels feel sturdy, and the single-lever height adjustment moves smoothly and clicks securely into its seven positions.

However, we must address a significant discrepancy right away. The official product specifications list the item weight at a feather-light 21.65 pounds. Let me be clear: this is unequivocally incorrect. As one user discovered upon delivery, the shipping box weighs over 80 pounds. The mower itself, once unboxed and with the battery installed, feels closer to 65-70 pounds. While it’s still manageable and far from the heaviest mower on the market, anyone purchasing this based on the 21-pound spec—perhaps for lifting over retaining walls or carrying up stairs—will be in for a shock. Despite this error in the listing, the actual weight feels appropriate for a durable, steel-decked machine, and it contributes to a sense of stability during operation. You can see its full feature set and correct user-reported weight details on its product page.

Deep Dive: Putting the Greenworks Mower to the Test

A mower can look great out of the box, but the real test is how it performs on the lawn. Over several weeks, we put the Greenworks 21″ Self-Propelled Lawn Mower 5.0Ah through its paces on a variety of turf conditions, from a manicured suburban lawn to a patch of thicker, slightly damp Kentucky bluegrass. We evaluated its cutting power, the effectiveness of its self-propel system, the all-important battery life, and its overall ergonomics.

Raw Cutting Power and Deck Performance

The heart of this machine is its high-efficiency brushless motor paired with that 21-inch steel deck. For standard weekly mows on dry or moderately dense grass, the performance is stellar. The blade spins at a high RPM, creating excellent lift that pulls the grass blades up for a crisp, even cut. We tested all three disposal options: mulching, bagging, and side discharge. The mulching function works exceptionally well, finely dicing the clippings and returning them to the lawn without leaving noticeable clumps. The rear bag is generously sized and easy to attach and detach, and the side discharge chute is a simple but effective solution for when the grass is a bit too long to mulch effectively.

However, we confirmed what some users have experienced: this mower has its limits. When we tackled a patch of overgrown, moisture-retaining bluegrass, the mower began to struggle. The motor would audibly strain, and if we pushed it too fast, it would choke up and stall. This isn’t a flaw unique to this model; it’s a common trait of battery-powered mowers compared to their high-torque gas counterparts. As one user wisely noted, this mower “works best when you stay on top of new growth.” If you mow regularly and avoid cutting wet grass, the power is more than sufficient. For those tackling tougher conditions, this powerful brushless motor is a feature that really sets it apart from less capable models, but it’s not a brush hog.

The Self-Propel System: A Back-Saver with a Big Appetite

The self-propel feature on the Greenworks 21″ Self-Propelled Lawn Mower 5.0Ah is, for many, the main reason to choose it over a standard push model. Activated by a separate bail bar on the handle, the rear-wheel drive engages smoothly and provides a surprising amount of pull. It makes climbing moderate inclines feel effortless and turns mowing a large, flat lawn into a leisurely stroll. The variable speed is responsive, allowing you to match the mower’s pace to your own walking speed. For anyone who has struggled to push a heavy, bag-laden mower up a slope, this feature alone is worth the price of admission.

But this convenience comes at a significant cost: battery life. This was the single most consistent piece of feedback we found, and our tests confirmed it completely. Engaging the self-propel system dramatically increases the load on the battery. As one user succinctly put it, “Using the self propelled function cuts your battery life in half.” Without the self-propel, we could easily achieve 35-40 minutes of runtime on a standard lawn. With the self-propel running continuously, that time plummeted to just 20-25 minutes. This is a critical trade-off to understand. If you have a smaller, flatter yard, you may find—as some users did—that the mower is light enough to push manually, saving the battery for cutting. If you need the self-propel, you must factor its energy consumption into your lawn care plan.

Battery Life and The 40V Ecosystem Reality

This brings us to the most debated aspect of the Greenworks 21″ Self-Propelled Lawn Mower 5.0Ah: the battery. Greenworks claims up to 45 minutes of runtime from the included 5.0Ah battery. In our testing, this is an optimistic, best-case scenario—achieved on a very light, dry, short lawn without using the self-propel feature. A more realistic expectation for a typical suburban lawn with varied grass density is around 30-35 minutes as a push mower, and 20-25 minutes using self-propel. For many users with yards of a quarter-acre or less, this is perfectly adequate. You can mow the lawn, pop the battery on the charger, and be done.

However, for those with larger properties, the single included battery is simply not enough. We heard from users with 3/4-acre lots who needed two full charges to finish the job. The consensus is clear: if your yard takes more than 30 minutes to mow, you should plan on investing in a second battery. This allows you to have one charging while the other is in use, enabling continuous operation. The good news is that this 40V battery is part of a massive ecosystem of over 75 other Greenworks tools, from string trimmers and leaf blowers to chainsaws. If you’re already invested in or plan to build out a collection of cordless yard tools, this shared battery platform adds tremendous value and makes the cost of an extra battery much more palatable. You can check the latest price and availability on this mower and its compatible batteries.

What Other Users Are Saying

Diving into the pool of real-world user feedback provides a remarkably clear and balanced picture of this mower’s strengths and weaknesses. The sentiment is generally positive, with most praise centering on the core benefits of battery power. One first-time mower owner was thrilled, saying, “Loving it so far… the mower is super easy to maneuver. The standing storage feature is a blessing, takes very little space.” Another user, who was able to mow their entire 3/4 acre lawn in 35 minutes (without self-propel), found it “exceeded my expectations.”

On the flip side, the theme of insufficient battery life is unavoidable. One user was “devastated” when the battery died before they could even finish their backyard, noting it only lasted 15 minutes. Another stated plainly, “I suggest buying a second battery so you can swap batteries while mowing.” The most concerning feedback, however, points to potential quality control lapses. One user described a terrifying experience where the mower, upon battery insertion, “ran me over knocking me to the ground” due to a faulty switch. While this appears to be a rare and extreme outlier, it serves as a crucial reminder to always handle powerful equipment with care and to test all safety features immediately upon receipt.

How Does It Compare? The Greenworks vs. The Competition

The Greenworks 21″ Self-Propelled Lawn Mower 5.0Ah exists in a crowded market. To understand its place, let’s compare it to three distinct alternatives that cater to different needs and priorities.

1. CRAFTSMAN 20-Inch Corded Electric Lawn Mower

The Craftsman Corded Electric Mower represents a different approach to gas-free mowing. Its primary advantage is unlimited runtime; as long as it’s plugged in, it will run. It’s also typically more affordable and lighter than its battery-powered counterparts. However, the cord is its defining limitation. You are constantly managing the cord to avoid running over it, and your range is limited by the length of your extension cord. This makes it an ideal choice for someone with a very small, simple, and flat yard where cord management is not a significant hassle. It’s not suitable for yards with many trees, garden beds, or other obstacles to navigate.

2. Greenworks 40V 20″ Brushless Push Mower 4.0Ah

This is the direct, non-self-propelled cousin to the mower we’ve reviewed. By ditching the self-propel motor, it gains two key advantages: it’s lighter and achieves a longer runtime from a comparable battery. It features a slightly smaller 20-inch deck but shares the same excellent brushless motor technology and 40V battery platform. This model is the perfect alternative for someone with a small-to-medium-sized flat lawn who doesn’t need or want the powered wheel assistance. If you want to maximize your runtime and save a bit of money while staying in the Greenworks ecosystem, this is an excellent choice.

3. Fiskars 18″ Manual Reel Mower

The Fiskars Reel Mower is the ultimate eco-friendly, minimalist option. It uses no gas, no oil, and no electricity. Its power source is you. It’s nearly silent, requires almost no maintenance beyond blade sharpening, and provides a unique, scissor-like cut that is very healthy for grass. However, it’s only practical for very small, well-maintained lawns. It cannot handle tall weeds, twigs, or bumpy terrain. This is for the lawn care purist who enjoys the exercise and simplicity, and has a small, green postage stamp of a yard to prove it.

Final Verdict: An Excellent Mower for the Right Yard

After extensive testing and analysis, our verdict on the Greenworks 21″ Self-Propelled Lawn Mower 5.0Ah is overwhelmingly positive, but it comes with an important qualification. This is a fantastic machine that delivers on the promise of quiet, convenient, and low-maintenance lawn care. The push-button start, powerful cut, solid steel deck, and game-changing vertical storage make it a joy to use. The self-propel feature is a genuine back-saver that makes mowing hilly terrain feel effortless. It is an ideal choice for homeowners with lawns up to a third of an acre who are tired of the noise, fumes, and maintenance of gas mowers.

The critical factor, however, is battery management. You must go into this purchase with the understanding that the 45-minute runtime is a best-case scenario and that heavy use of the self-propel feature will significantly reduce it. For yards approaching half an acre, or for those who will rely heavily on the self-propel function, a second battery is not a luxury—it’s a necessity. If you have the right expectations and the right-sized yard, this mower will transform your lawn care routine for the better. If you’re ready to ditch the gas can and pull-cord for good, we highly recommend you explore the full details and purchase the Greenworks 21″ Self-Propelled Lawn Mower 5.0Ah today.