Greenworks Replacement Lawn Mower Blade

Why I swapped blades and what changed

My Greenworks corded 20-inch mower had started leaving stragglers and tearing rather than cutting cleanly. After a couple of touch-up sharpenings on the stock blade, it was time for a true replacement. I installed the Greenworks replacement blade and put it to work for a full season on a mix of cool-season turf and a patch of thick, moisture-holding St. Augustine. The difference in finish quality, motor load, and bagging efficiency was immediately noticeable.

Compatibility and fit

This blade is purpose-built for Greenworks’ 20- and 21-inch corded mowers, notably the 25022 and 25112. The actual cutting length measures 19.69 inches, which matters because a lot of “20-inch” blades in the aftermarket space vary by several millimeters. On the 25022 deck, the clearance was spot on—no rubs, no contact with the shell or baffles, and the cutting path matched the deck width as expected.

The mounting interface aligned with the mower’s spindle and spacer without fuss. If you’re coming from a worn or bent blade, check your spindle and adapter for damage; the blade won’t fix underlying mechanical issues. Also worth noting: the blade ships without hardware, so plan to reuse your factory bolt and washer.

Installation experience

Swapping the blade is straightforward, but do it safely:
- Unplug the mower and remove any safety key.
- Wear gloves and block the blade with a wood scrap.
- Loosen the bolt, noting the orientation of the old blade.

The new blade seated flat, and I torqued it to the manufacturer’s spec. Out of the box, balance was excellent—I checked it on a simple cone balancer and didn’t need to remove material. A balanced blade makes a big difference in vibration and bearing wear, and this one was true.

Build quality and design

The blade is forged from a single piece of steel, and the one-piece construction translates into good stiffness and edge stability. The black coating is even and held up decently on the body of the blade; as with any blade, the finish near the cutting edge burns off quickly under use and sharpening. The stock grind is consistent and sharp along both edges.

This is a general-purpose cutting profile that works across mulching, bagging, and side discharge. It’s not an extreme high-lift design, but it produces more than enough airflow for most bagging and does a respectable job mulching leaves as long as you don’t let piles get ankle-deep.

Cutting performance

On fresh turf, the blade delivered a noticeably cleaner cut than my worn original. The motor maintained speed better in dense patches, which I attribute to both the fresh edge and a slightly more aggressive leading edge than my old blade had after repeated sharpenings. Here’s how it performed in specific scenarios:

• Weekly maintenance cuts: Even finish with fewer uncut wisps, especially along the mower’s overlap lines. The stripe is more defined simply because the grass is cut to a uniform height.
• Damp grass: The blade still produced a clean slice, not a ragged tear. I made sure to reduce walking speed slightly to avoid bogging, and the mower kept up fine.
• Overgrown areas: In sections that were 1–2 inches taller than normal, I made a single pass at a higher deck setting and a follow-up at my usual height. The blade cleared clippings well and didn’t leave clumps unless the grass was very wet.
• Edges and obstacles: After occasional encounters with twigs and sandy edges along a walkway, the edge picked up minor dings—as any blade will—but remained serviceable. A quick file pass brought the edge back without chasing a burr across the entire bevel.

Bagging and mulching

Airflow is strong enough that my bag filled evenly from corner to corner. Compared to my tired blade, lift improved the way grass stood up before the cut, which means fewer lay-downs and a more even height. For mulching, it chopped leaf litter into small pieces in one or two passes; not as pulverized as a dedicated mulching blade with serrations or extra trailing flutes, but plenty fine for mid-season cleanup. If you primarily mulch heavy leaves in the fall, a specialty blade could eke out a bit more finesse, but for all-around mowing this one hits the right balance.

Noise and vibration

With the blade balanced well, vibration was negligible. On a corded mower, any imbalance is immediately obvious at the handle; I didn’t get the tingle or chatter that often creeps in with cheaper replacements. Noise was typical for this mower—no whistle or droning that sometimes occurs with oddball profiles. If you’re hearing more noise than usual after installing any blade, recheck torque, orientation, and deck clearance.

Durability and maintenance

Across a full mowing season, edge retention was solid. I sharpened twice: once mid-season and again before fall cleanup, using a file and finishing with a quick balance check. The steel takes an edge cleanly and doesn’t chip easily under normal lawn care abuse. I avoided rocks, but I did hit the occasional acorn and stick without dramatic damage.

If you store the mower in a humid space, wipe the blade and spritz a light coat of oil after your final mow of the year to fend off surface rust. The coating on the blade body helps, but the bare cutting edge benefits from protection.

Practical tips for best results

• Match the blade to the mower model. The 19.69-inch length and specific mounting pattern are designed for Greenworks’ 20/21-inch corded decks. Close isn’t good enough with blades—get the exact fit.
• Keep it sharp and balanced. Touch up lightly rather than waiting until the edge is rounded over. A few passes with a file on each side, maintaining the existing bevel, is often all you need.
• Mind the deck height in thick grass. One higher pass followed by a finish pass gives a better result and is easier on the motor.
• Reuse the OEM hardware. If your bolt or washer is chewed up, replace them before running a new blade.

Where it lands in value

As an OEM-matched option, this blade offers the fit and finish you expect without playing compatibility roulette. Given the build quality and how well it holds an edge, it’s a strong value for anyone maintaining a small to medium yard with a Greenworks corded mower. There are cheaper blades out there, but you tend to give up balance consistency and exact fit. For me, the reduction in vibration alone is worth sticking with a proper match.

The bottom line

The Greenworks blade brought my corded mower back to its best behavior: cleaner cuts, steadier motor speed in dense patches, and better bagging. It installed without fuss, ran smoothly, and held an edge through a busy season with routine maintenance. It’s not a specialty mulching blade, but as an all-purpose cutter for regular lawn care, it delivers exactly what a compatible Greenworks deck needs.

Recommendation: I recommend this blade for owners of Greenworks 20- and 21-inch corded mowers who want an exact-fit replacement with dependable cutting performance and low vibration. It’s a straightforward way to restore your mower’s finish quality without compromising on balance or durability. If you’re running a different brand or deck size, look for the correct model rather than forcing a near match—blades are not the place to improvise.