Quick verdict
Greenworks' 40V dethatcher swaps between spring-tine and scarifier reels without tools, adjusts depth across five positions and runs on the same battery as the brand's 75-plus 40V tools, with no cord across the lawn. It is sold bare. For lawns beyond cord reach it is the dethatcher to buy, provided you own or add a 4.0Ah or larger battery.
Strengths
- Cordless; no extension cord across the lawn
- Quick-swap dethatcher and scarifier reels included
- Five-position depth adjustment
- Shares batteries with more than 75 Greenworks 40V tools
- Three-year tool warranty
Weaknesses
- Battery and charger not included
- Runtime on small packs is short for a big lawn
- No collection bag; raking follows
The overall YardToolLab Score is out of 100. Section scores are out of 10.
Dethatching Without the Cord
Corded dethatchers are cheap and effective but tethered. Greenworks’ 40V dethatcher cuts the cord: a battery-powered unit with quick-swap dethatching and scarifying reels, five depth positions and a 14 inch working path, running on the same 40V battery as the brand’s trimmers, blowers and chainsaws. It is sold as a bare tool.
This review is based on Greenworks’ specifications and on owner feedback rather than on our own use.
Thatch Removal
With the spring-tine reel fitted and a shallow first pass, owners report the same bags of brown thatch that corded machines pull, and a visibly greener lawn in the weeks after. The scarifier reel cuts shallow slits into the surface for overseeding. Depth adjusts from above the surface to three quarters of an inch below for dethatching, and Greenworks’ guidance on timing, early spring or early autumn for cool-season grass and late spring for warm-season, matches standard lawn practice.
Cordless Convenience
No cord means no planning rows around an extension lead and no reach limit. Owners with lawns far from an outlet rate this as the whole reason to pay more than a corded unit. The machine is light and the handle folds for storage.
Battery and Runtime
Runtime depends on the pack. A 4.0Ah battery covers a typical suburban lawn in owner reports; large lawns or deep thatch want a larger or second pack. Because the battery is shared across more than 75 Greenworks 40V tools, many buyers already own one, which is the only way a bare tool makes sense.
Reel Swap
Changing between reels takes a minute without tools, and owners find the mechanism positive. Both reels are included.
Collection
There is no bag. Thatch lies on the surface for raking or for the mower’s bagger to collect, which owners find quicker than emptying a small dethatcher bag anyway.
Who Should Buy It
- Greenworks 40V owners with a thatchy lawn.
- Lawns beyond cord reach of an outlet.
- Anyone overseeding who wants the scarifier function.
Common Owner Complaints
Bare-tool pricing, runtime on small batteries and the raking that follows. Performance complaints are rare.
Technique Tips
Mow the lawn short the day before, start with the tines set at or just above the surface, and make a first pass to see how much thatch lifts before going deeper. A second pass at right angles reaches thatch the first missed. Rake or bag the debris, then overseed and water, since the open surface is the best seedbed of the year. Owners keep the spare reel in its box so the tines stay straight between seasons.
Alternatives to Consider
The Sun Joe AJ805E is the corded value choice with a bag. Agri-Fab’s tow-behind dethatcher suits tractor owners. A manual dethatching rake handles small patches.
Verdict
For 40V owners and for lawns a cord cannot reach, the Greenworks dethatcher does the job of a corded machine with none of the tether. Fit a 4.0Ah battery, start shallow and rake afterwards, and the lawn will thank you by midsummer.
Full specifications
Greenworks 40V 15 Inch Dethatcher and Scarifier, Tool Only FAQs
A 4.0Ah Greenworks 40V pack covers a typical suburban lawn in owner reports. Larger packs or a spare suit bigger lawns.
Early spring or early autumn for cool-season grass; late spring after the second mow for warm-season grass, as Greenworks advises.
No. It leaves thatch on the surface for raking or mowing with a bagger.
Dethatcher tines comb out dead grass. Scarifier blades cut into the soil surface, which is more aggressive and ideal before overseeding.
