An honest, experience-led review of Greenworks 40V 21" self-propelled cordless lawn mower user reviews, covering real-world performance, mixed feedback, and whether it justifies the $450–$500 price tag.
Greenworks 21" Self-Propelled Cordless Lawn Mower Reviews
A Bigger, More Ambitious Cordless Mower - The Greenworks 40V 21-inch self-propelled cordless lawn mower is clearly aimed at homeowners who want to step beyond entry-level electric mowers. With a wider steel deck, a brushless motor, rear-wheel self-propulsion, and a 5.0Ah battery included, it sits firmly in the mid-to-upper price bracket for battery-powered mowers in the US market, typically selling between $450 and $500.
Lots of Promises
On paper, it promises a lot. The self-propelled system is designed to reduce effort on slopes or larger lawns, while the 21-inch cutting width should help reduce mowing time compared to smaller cordless models. Features like variable speed control, LED headlights, and a 4-in-1 cutting system suggest this mower is built for convenience rather than just basic maintenance.
Mixed Reactions
That said, user feedback paints a more nuanced picture. There are plenty of positive reviews praising the mower’s quiet operation, ease of use, and freedom from gas and oil. At the same time, mixed reviews raise questions about battery longevity under load, real-world runtime when using self-propelled drive, and whether the overall build quality matches its premium pricing.
Key Features Worth Noting
The brushless motor is often highlighted as a strength, supporting smoother operation and potentially longer lifespan compared to brushed designs. The mower runs on Greenworks’ 40V ecosystem, which may appeal to homeowners already using compatible tools. I think that ecosystem value matters, but only if the mower itself stands up over time.
With a listed weight of just under 74 pounds, this is not a light machine, although the self-propelled drive is meant to offset that. Assembly is required, and early experiences vary depending on expectations and familiarity with cordless equipment.
Months of Use
Before getting carried away by feature lists or marketing claims, it’s worth digging into what real owners say after weeks or months of use. That is where this review focuses, looking at positive, mixed, and negative experiences to help you decide whether this mower fits your lawn and your budget.
Positive Reviews - What Owners Like
Looking through the 5-star feedback, a few clear themes come up again and again. Most positive reviewers focus on ease of use, quiet operation, self-propelled control, and the freedom from gas and oil. Many of these reviews come from people who were either new to mowing, returning after years of gas mowers, or physically limited users who specifically needed something manageable.
Easy Assembly and Straightforward Setup
One of the most consistent positives is how simple the mower is to get up and running. Several users mention that assembly takes very little time and does not feel intimidating, even for first-time owners.
Comments repeatedly describe it as “super easy to assemble” and “very easy to assemble and use”. For some, this was a major upgrade compared to older gas models where setup and maintenance felt like chores. One review summed it up simply, saying it was “easy to assemble and easy to start up”, with controls “right at your fingertips”.
There are occasional mentions of minor setup quirks, such as needing to tuck wiring neatly into the handle, but these were generally seen as small, manageable issues rather than deal-breakers.
Quiet Operation and No Gas Hassle
Noise reduction is a big selling point for many buyers, and positive reviewers strongly echo this. Owners frequently compare it favorably to gas mowers, noting how much quieter it feels in real use.
Phrases like “very quiet”, “3x quieter than gas feels accurate”, and “you can work on a weekend without disturbing neighbors” come up repeatedly. Several users explicitly mention enjoying not having to deal with gas, oil, or pull cords anymore, describing the experience as “just charge and go”.
One reviewer described the switch as something they wished they had done sooner, noting “no more messing with gas or oil, that’s how I like it”. For people living in noise-sensitive neighborhoods, this quiet operation seems to be one of the mower’s strongest advantages.
Self-Propelled System and Adjustable Speed
The self-propelled feature earns a lot of praise, particularly the variable speed control. Many users appreciate that it does not force you to move too fast and can be adjusted to match different walking speeds.
Several reviews mention liking that “the slow speed is truly slow” and that it gradually increases rather than jumping straight to an aggressive pace. This mattered especially to older users or those with mobility limitations, who felt more in control compared to earlier self-propelled designs.
One long, detailed review highlighted how this specific model improved on older Greenworks versions by allowing smoother backing up and quicker wheel release, making maneuvering around trees, fences, and bushes far less frustrating.
Cutting Performance on Regularly Maintained Lawns
When used as intended, meaning on lawns that are cut regularly, many reviewers say the mower performs very well. Descriptions like “cuts grass like butter”, “cuts beautifully”, and “does the job” are common.
Some owners mention mowing damp grass, clover, or slightly taller growth and still getting acceptable results. One review noted that even with knee-high grass, the mower “still does the job”, though runtime was reduced. Others emphasize that weekly mowing delivers the best results, especially when mulching.
The 21-inch deck is often appreciated for helping reduce mowing time, and the mulching function is commonly used, with fewer owners choosing bagging or side discharge.
Battery Runtime for Small to Medium Lawns
Battery performance is viewed positively by many 5-star reviewers, particularly those with small to medium-sized yards. Several mention runtimes between 30 and 45 minutes, depending on conditions and use of self-propel.
One user reported mowing about 0.2 acres while using self-propelled drive and still having “about 50% battery left”. Another noted that when pushing manually without self-propel, “it runs about an hour and the battery is still good”.
While not everyone expects the battery to handle very large properties, many felt it was “just right” for their needs, especially if mowing weekly and not letting grass get out of control.
Design Details and Storage Convenience
Smaller design touches also get mentioned positively. The folding handle and vertical storage option are appreciated by people with limited garage space, with comments like “I love the space-saving feature to fold and stand”.
The LED headlight is often described as a bonus rather than a necessity, but several reviewers found it genuinely useful when daylight ran short, calling it “a nice extra” that made the mower feel more thoughtfully designed.
Overall build quality is described by positive reviewers as solid and durable, with some long-time Greenworks users expressing brand loyalty based on previous models lasting many years.
Suitable For a Wide Range of Users
What stands out is how many different types of users leave positive reviews. These include older homeowners, people with health limitations, first-time lawn mowers, and those downsizing from gas equipment.
One particularly striking review came from someone mowing for the first time at age 73, describing the mower as manageable, adaptable in height, and empowering. Others mention being able to mow despite physical limitations, saying it “does all the work for you” and feels far less demanding than traditional mowers.
Overall Sentiment from Positive Reviews
Taken together, the positive feedback suggests that when expectations are realistic, and the mower is used on a regularly maintained lawn, the Greenworks 40V 21" self-propelled mower can be quiet, convenient, and genuinely enjoyable to use. Many reviewers describe it as good value for money when purchased on sale, and several explicitly say they would recommend it to others in similar situations.
That said, even within the 5-star reviews, there are subtle hints about limitations, particularly around battery capacity and weight, which become more prominent when we look at mixed and negative feedback in later sections.
Mixed Reviews – Where it Impresses and Where it Frustrates
The mixed reviews paint a very clear picture of a mower that can work well in the right conditions, but one that asks buyers to adjust expectations, mowing habits, and sometimes budgets. Most 3 to 4-star reviewers like the mower itself, but struggle with battery life, weight, or performance in thicker grass.
This section is especially important because many of these reviewers wanted to love the mower, and in some cases eventually did, but only after compromises.
Cutting Performance Is Generally Solid, With Limits
A common theme is that the mower does cut well, provided you work within its comfort zone. Several reviewers say things like “it cuts right through even tall thick grass” and “cuts nicely”, but these comments are often followed by caveats.
Some users found that when grass was overgrown, wet, or particularly dense, the mower could bog down, shut off, or require height adjustments. One reviewer explained that mowing two weeks of growth caused the mower to stop until they raised the cutting height, after which “it worked fine”.
Others described the experience as needing to “learn how to mow with an electric”, adjusting blade height and mowing frequency to reduce strain on the motor and battery.
Battery Life is the Main Pain Point
Battery performance dominates nearly every mixed review. While some users found the runtime acceptable, many felt it fell short of expectations, especially given the mower’s price.
Comments like “battery just don’t last enough to finish cutting 7000 sqft”, “charge is only for 45 minutes, not recommended for large lawn”, and “I have to recharge it at least three times to finish mowing” appear repeatedly.
Even among satisfied owners, it is commonly acknowledged that a second battery is almost essential unless you have a small yard. One reviewer put it bluntly, saying “a 2nd battery is needed if your yard is not small”. Another said the mower is “great, but you may need extra batteries when using self-propelled”.
Some users also reported overheating warnings, flashing red charger lights, and the need to let the battery cool before charging again, which extended mowing sessions across hours or even days.
Self-Propelled Feature - Helpful But Power-Hungry
The self-propelled system is generally appreciated, particularly on hills, but it comes at a cost. Many reviewers note that using self-propelled drive dramatically reduces runtime.
One user mentioned getting “only 10–15 minutes when using self-propelled going uphill”. Another explained that they only use self-propel on inclines to conserve power. This trade-off seems acceptable to some, but disappointing to others who expected consistent runtime regardless of drive mode.
There are also mixed comments about maneuverability. While some say it is light and easy to handle, others describe it as “somewhat awkward to maneuver” or simply too heavy for elderly users, even with self-propel engaged.
Weight And Handling Divide Opinions
Weight is another recurring theme. Some reviewers describe the mower as “nice and lightweight” and “easy to maneuver”, while others say it is too heavy, particularly for older users or those with physical limitations.
One 4-star review explained that although the mower had “all the features we wanted”, it had to be returned because it was “just too heavy for us to handle”. Another reviewer noted that it is “heavy for a 20-inch mower”, even if the propulsion helps offset that.
This suggests that perceived weight depends heavily on user strength, terrain, and whether self-propel is relied on constantly.
Instructions and Learning Curve
Several mixed reviews mention that the instructions are vague or overly pictorial. One reviewer noted that “instructions are very vague, must be internet competent”, while another detailed having to figure out control combinations through trial and error.
There is also a learning curve in understanding how to operate propulsion separately from blade engagement, how to release the wheels properly, and how to avoid battery drain through mowing technique. For users willing to adapt, this becomes manageable. For others, it adds unnecessary frustration.
Build Quality and Design Quirks
Most mixed reviewers feel the build quality is reasonable for the price, but not premium. Comments like “reasonable for price” and “you get what you pay for” appear often.
A few users mention specific quirks, such as the battery shifting and shutting off on uneven ground, the blade hitting the chute cover, or the actual cutting width being slightly under the advertised 21 inches. These issues are not universal, but they do contribute to the sense that quality control may be inconsistent.
Long-Term Satisfaction Improves with Adjustments
Interestingly, some of the most detailed mixed reviews include updates where opinions improve over time. One reviewer initially struggled with battery drain and overheating but later said “I love it now” after adjusting mowing height, planning recharges, and accepting that two charges were needed for a 10,000 sq ft yard.
This suggests that for some owners, satisfaction increases once expectations align with reality. Others, however, remain frustrated, especially those who feel the battery claims are misleading.
Overall Sentiment from Mixed Reviews
The mixed reviews show a mower that performs well in ideal conditions but asks buyers to compromise. The cutting ability, quiet operation, and ease of starting are widely appreciated. Battery life, however, consistently undercuts the experience, especially for medium to large lawns or users expecting gas-like endurance.
Many reviewers ultimately recommend the mower with conditions, often suggesting buying extra batteries, mowing more frequently, or even stepping up to a higher-voltage model. For the right user, it can be a good fit. For others, it may feel underpowered and inconvenient.
Negative Reviews - Where Things Break Down
The negative reviews for the Greenworks 40V 21" Self-Propelled Cordless Lawn Mower are unusually consistent, both in tone and in the issues raised. While individual complaints vary in intensity, the same problems come up again and again, across different states, lawn sizes, and usage habits. This consistency matters, because it suggests these are not isolated lemons, but recurring weaknesses.
Below are the main themes, using reviewers’ own words where they help illustrate the experience.
Battery Life Falls Well Short of Expectations
By far the most common complaint is battery runtime, and not by a small margin. Many 1 and 2-star reviewers report real-world runtimes of 10 to 20 minutes, even on modest lawns.
Comments like “lasts maybe 15 minutes”, “battery lasts about 10–12 minutes”, and “not even close to what’s advertised” appear repeatedly. Several reviewers explicitly compare their yard size to the claimed coverage and say it simply does not line up.
One reviewer summed it up bluntly: “A battery-powered mower that can’t mow a small yard with one battery is useless.” Even users who liked the mower’s cutting ability often said the battery made the entire system impractical.
Recharge Times Add to the Frustration
Battery life issues are compounded by long recharge times. While the product listing suggests around two hours, many reviewers report 3 to 5 hours per charge, sometimes longer.
As one buyer put it: “Why does a battery need 2 hours to charge to only last 10 minutes?” Another noted that with multiple batteries, mowing stretched across “multiple days” due to cooling and charging delays.
This turns what should be a one-session job into a stop-start process that many found unacceptable for a mower in the $450 to $500 range.
Power Loss, Stalling and Constant Shut-Offs
A large number of negative reviews describe the mower bogging down, stalling, or shutting off repeatedly, even when grass is not excessively tall or wet. Examples include…
- “Shuts off every 3–4 seconds”
- “Bogged down about 25 times per mow”
- “Stops constantly and needs to be restarted”
Some users say the mower overheats, others mention the battery showing charge remaining but refusing to run. In humid climates, particularly Florida and Texas, reviewers say performance drops sharply even with dew or slightly damp grass. One reviewer wrote: “If it rained last weekend, this weekend is going to be rough.”
Battery Reliability and Longevity Concerns
Beyond short runtime, there are serious concerns about battery durability. Several owners report batteries failing after only a handful of uses or degrading sharply within a year.
One long-term user explained that batteries which once handled most of their yard now “can’t even get through a third”, despite owning multiple Greenworks batteries of different sizes.
Others describe batteries overheating, refusing to charge, blinking error lights, or dying completely after two or three cycles. Given that replacement batteries can cost a significant portion of the mower’s price, this becomes a major financial concern.
Build Quality and Design Complaints
Some negative reviews point to physical design flaws…
- Batteries popping loose over small bumps
- Grass clogging under the deck
- Blade hitting chute covers
- Self-propel pulling too aggressively or inconsistently
A few reviewers also mention assembly issues, unclear instructions, missing parts, or controls that feel awkward or unintuitive. While not universal, these complaints add to the sense of inconsistent quality control.
Customer Support Experiences Add Fuel to the Fire
Several frustrated buyers mention poor customer service experiences. Long wait times, scripted responses, difficulty getting replacements, and limited troubleshooting support come up more than once.
One reviewer said, “You’re going to wait forever, only to talk to a person who knows absolutely nothing about the product.” Others report being pushed to websites instead of speaking to someone directly.
For buyers already dealing with a half-mowed lawn, this clearly worsened the experience.
Regret And Returns Are Common Themes
Many negative reviews explicitly mention regret, missed return windows, or switching back to gas mowers. Statements like “I wish I had saved my money”, “I was almost relieved when it stopped working”, and “I’ll never go back to Greenworks” are strong signals of dissatisfaction.
A recurring sentiment is that while the idea of electric mowing is appealing, this particular execution left buyers feeling let down.
Overall Sentiment from Negative Reviews
Taken together, the negative reviews suggest that the mower’s biggest weakness is not one isolated flaw, but a stack of battery-related limitations that undermine the entire experience. Short runtime, long charging, overheating, and degradation over time combine to make mowing feel unpredictable and stressful for many owners.
While some users acknowledge that the mower cuts well when it runs, the overwhelming feeling is that reliability and endurance simply do not meet expectations for the price. For buyers who value consistency and want to finish their lawn in one go, these reviews raise serious red flags.
Pros & Cons - Who It May Suit, And Who Should Probably Look Elsewhere
Based on the full spread of user feedback, including strong praise and a large volume of complaints, this mower sits firmly in “mixed but leaning risky” territory. There are things it does reasonably well, but there are also limitations that are hard to ignore if you are spending your own money. Here is a balanced, experience-led breakdown…
Pros for the Greenworks 21 Inch SP Cordless Lawnmower
1, Quiet Operation Compared to Gas - Many users appreciate how much quieter this mower is than traditional gas models. It supports early morning or weekend mowing without annoying neighbours, which I think is one of the genuine benefits of going electric.
2, Easy Start and Low Day-To-Day Maintenance - When it works properly, starting is simple. No pull cords, no gas, no oil, and minimal routine maintenance. Several owners liked the idea of just charging the battery and getting on with the job.
3, Self-Propelled Feature Helps Reduce Effort - For those who had no battery issues, the self-propelled system was often praised. Adjustable speed control helps match walking pace, which may improve comfort for older users or anyone with mobility concerns.
4, Decent Cut Quality on Regularly Maintained Lawns - On short, dry grass, many reviewers say it cuts evenly and cleanly. Mulching, bagging, and side discharge options give flexibility depending on lawn condition.
5, Folding Handle and Space-Saving Storage - The fold-and-stand design was frequently mentioned as useful for garages or sheds with limited space. It stores neatly when not in use.
6, No Fuel Smell or Emissions - Several buyers liked avoiding gas stations, fumes, and engine smells altogether. From a convenience and comfort standpoint, that is a fair plus.
Cons for the Greenworks 21 Inch SP Cordless Lawnmower
1, Battery Runtime is Widely Reported as Poor - This is the biggest drawback and the most consistent complaint. Many owners report real-world runtimes of 10–20 minutes, even on modest lawns. For a self-propelled mower of this price, that is difficult to overlook.
2, Long and Inconsistent Charging Times - Recharge times are often reported at 3–5 hours, not the advertised figure. This makes same-day mowing difficult unless multiple batteries are owned.
3, Extra Batteries add Significant Cost - Replacement batteries are expensive. Several reviewers ended up spending hundreds more just to finish their lawn, which changes the value equation completely.
4, Performance Drops in Damp or Thicker Grass - The mower may struggle with even slightly damp grass, thicker growth, or missed mowing cycles. Stalling and shutdowns are commonly reported in these conditions.
5, Battery Reliability and Degradation Concerns - Some users experienced batteries failing after very limited use or losing capacity within a year. That kind of uncertainty is a real concern for long-term ownership.
6, Frequent Stalling and Shut-Off Issues - Repeated stopping, bogging down, and restart problems made mowing frustrating for many users, even on well-kept lawns.
7, Build and Design Quirks - Complaints include batteries popping loose, clogging under the deck, aggressive self-propel behaviour, and awkward battery insertion. None are universal, but they appear often enough to matter.
8, Mixed Customer Support Experiences - Long wait times and limited solutions left some owners feeling unsupported, particularly when the mower failed early.
Who This Mower is For
- Homeowners with very small lawns, possibly under 500–800 sq ft
- People who mow frequently and keep grass short and dry
- Buyers who already own multiple compatible Greenworks batteries
- Users who prioritise quiet operation and low effort over runtime
- Those with storage constraints who value fold-up design
If everything lines up, short grass, light use, and extra batteries, it can function acceptably.
Who This Mower is Not For
- Medium to large yards expecting to mow in one session
- Buyers relying on a single battery
- Anyone mowing every 7–10 days or dealing with thicker grass
- Humid or damp climates where grass resistance is higher
- Users who want predictable runtime and minimal interruptions
- Anyone uncomfortable with the risk of early battery failure
If finishing your lawn in one go matters to you, or if you expect performance close to advertised figures, I reckon this mower could become frustrating fairly quickly.
Final Rating: ⭐⭐☆☆☆ (2 out of 5)
After working through a large volume of real user feedback, I think a 2-star rating is a fair and defensible place for the Greenworks 40V 21" self-propelled mower to land.
On paper, it looks appealing. Quiet operation, no gas, push-button start, self-propelled assistance, and a decent cut when conditions are right. And to be clear, some users genuinely like this mower, especially those with very small lawns who mow often and already own spare batteries. In those narrow circumstances, it can do what it claims, at least for a while.
However, when you zoom out and look at the overall experience, the battery performance issues dominate the story. Runtime falling well short of expectations is not an occasional complaint here, it is the most common theme across mixed and negative reviews. Many buyers report 10 to 20 minutes of usable cutting time, even on modest lawns, followed by long recharge waits. That alone makes routine lawn care far more fragmented than most people expect.
Conclusion
I also think the cost equation quietly breaks down. Once you factor in the need for extra batteries, sometimes two or three, the mower stops feeling like a practical mid-range option and starts creeping into price territory where more powerful or more reliable alternatives exist.
Reliability concerns add another layer of risk. Reports of early battery degradation, stalling, overheating, and shutdowns make ownership feel unpredictable. Some users had no issues, others struggled from day one. That inconsistency matters when you are spending your own money and just want to mow your lawn without drama.
Final Word
Personally, I would struggle to recommend this mower unless someone had a very small yard and realistic expectations about stopping to recharge. For many buyers, especially those with average suburban lawns, I reckon frustration would outweigh the benefits fairly quickly.
In short, the Greenworks 40V mower supports light-duty use, but it does not reliably deliver the convenience or runtime most buyers expect. That gap between promise and real-world experience is why, despite some genuine positives, it earns only 2 stars overall.
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