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Deck material, mulch or bag, and cutting height
Updated
Three quieter specs decide how a mower feels to live with. Deck material sets the weight. The discharge modes decide what happens to the clippings. The top cutting height decides whether the mower can keep your grass as tall as it should be. Two picks here top out under 3.5 inches, and extension advice for cool-season lawns is 3 inches or higher.
Steel or plastic deck
Greenworks lists the deck on its 40V 16 inch mower as hardened plastic, and the mower at 37.8 pounds. It lists the 60V 21 inch self-propelled with a stamped steel deck at 65 pounds. Part of that gap is size and the drive, but the deck is a big share. Plastic does not rust and is easy to lift and hang. Steel stands up better to stones and to years of scraping. For a small yard and a push mower, light wins. For a big self-propelled mower, the drive carries the weight, so steel costs you little.
| Mower | Deck | Weight on the listing | Modes | Cutting heights |
|---|---|---|---|---|
| EGO LM2114 21 in push | 21 in | Not confirmed | Mulch, bag, side discharge | 1.25 to 4 in, 7 steps |
| EGO LM2114SP 21 in | 21 in | 50.9 lb | Mulch, bag, side discharge | 1.25 to 4 in, 7 steps |
| Greenworks 60V 21 in SP | 21 in steel | 65 lb | Mulch, bag, side discharge, leaf mode | 1.3 to 4.0 in, 7 steps |
| Greenworks 40V 16 in | 16 in plastic | 37.5 lb | Mulch, bag | 1-1/4 to 3-3/8 in, 5 steps |
| WORX WG779 14 in | 14 in polypropylene | 29.1 lb | Mulch, bag | 1.5 to 3.5 in, 6 steps |
| LawnMaster 19 in | 19 in, metal per the listing | 27 lb per the listing, unconfirmed | Mulch, side discharge | 1.4 to 3.4 in, 6 steps |
Mulch, bag or side discharge
2-in-1 usually means mulch and bag. 3-in-1 adds side discharge. Check which two you get. The LawnMaster listing names mulch and side discharge, with no bag. University of Minnesota Extension says leaving clippings on the lawn improves its health, so mulching is a fine default. Bag when the grass got away from you, and expect the battery to drain faster in that heavy cut.
Cutting height and the one-third rule
University of Minnesota Extension advises keeping a typical Midwest lawn at 3 inches or higher, and removing no more than 1/3 of the leaf at a time. To hold 3 inches, mow before the grass reaches 4.5. A mower that tops out at 3-3/8 or 3.4 inches can just do that. One that reaches 4 inches gives you room for the summer raise the same page suggests. Warm-season grasses are often kept shorter, so check advice for your own region.
The rule matters for the battery too. Cutting 1.5 inches off 4.5 inch grass is normal growth. Cutting 3 inches off a lawn that sat for two weeks is the "thick, tall" case in our calculator, where we plan on 60 percent of the claimed runtime.
The same page says to keep the blade sharp, because a dull blade shreds the grass tips. Take the battery out before you touch the blade.
Work out your own lawn with the mowing time calculator, or compare all six picks on the roundup page.