While there are generally accepted practices for cutting grass, there’s a lot of confusion when it comes to dealing with the clippings. Is mulching always the best option? Why shouldn’t you always bag clippings? Why would you want a rear discharge deck? Here’s what you need to know about how these methods work, and when you want to use them to deal with your lawn clippings.
Under most circumstances, mulching is the best choice for mowing. Mulching cuts grass clippings into tiny pieces, allowing their nutrients to be reabsorbed into the soil. Returning these clippings to the lawn also supports microorganism growth, acting as a sort of first course before microbes tackle the tough, woody material that makes up thatch. Done correctly, mulching reduces the need for fertilizer and keeps thatch buildup under control.
Modern mulching systems use high lift blades that act like fans, blowing clippings up into the deck’s mowing chamber. As the clippings fall back down, they’re sliced again. Large clippings continue to flow back into the mowing chamber, while small clippings fall between the blades onto the ground.
All that cutting can bog down the mower with clippings. To speed up this process, Honda’s Microcut system uses a pair of blades stacked on top of each other to slice clippings twice with each pass. Other manufacturers like Scag take a similar approach, adding serrated edges to the ends of their mulching blades to make two initial cuts before mulching.
In the past, there was a major difference in mulching performance between stamped and constructed mower decks. While a stamped deck can be shaped to hug the blades for increased vacuum, a constructed deck’s flat sides leaves the deck almost completely open. Today, manufacturers get around this by including baffles with their mulching kits. These metal plates seal the mowing chamber, improving vacuum. While you won’t get the finish of a stamped deck, the results are much closer than they were on older mowers.
Bagging is generally frowned upon in the landscaping community. By removing clippings, you’re stripping their nutrients from the soil. More fertilizer has to be added to the soil to compensate. However, there are times when you may not want clippings on your lawn:
– If weeds are germinating, mulching or discharging will spread their seeds across your lawn.
– While you can leave a thin layer of mulched leaves on your lawn for microorganisms to digest, a thick layer will block water and sunlight while turning acidic. Bagging removes leaves before they get out of hand.
– If you have black walnut trees, you may want to remove all leaves from your lawn. These leaves contain juglone, a chemical that is poisonous to a wide variety of plants.
The clippings you collect don’t have to go in the garbage. Instead, you can create a compost pile. Weed seeds, pollen and juglone break down after a few weeks, making the resulting mulch harmless to your lawn.
A side discharge system is the simplest way to deal with clippings. The blades cut the grass and push the clippings out of a chute on the side of the deck. Vacuum is still important to lift the grass and get an even finish, but there’s no need for tall mowing chambers, tight tolerances and high lift blades to get a good cut. However, the clippings left behind can clump together, and they don’t integrate into the soil as well.
Discharging takes less power than mulching, making this method a good choice for exceptionally tall or thick grass. To keep your lawn healthy, never cut more than one-third of the grass’s height at a time. If you need to get overgrown grass down to a manageable height, cut one-third of its length over multiple mows, letting the grass recover for a couple days between cuts.
Aside from some walk-behind mowers, a rear discharge deck cannot be adapted to bag or mulch clippings. However, letting the clippings leave the rear of the deck eliminates the need for a discharge chute. This makes rear discharge decks narrower than other decks. Since clippings are spread across the entire width of the deck, there’s less chance of clumping. Rear discharge mowers are a great choice for maximizing cutting width while keeping the mower small enough to weave through and around landscape features.
We Can Help You No Matter How You Mow
Need to upgrade your mower for mulching or bagging? Want to add a rear discharge mower to your fleet? No matter your needs, Shank’s Lawn Equipment can help you. We’re a dealer for most major mower brands, including Honda, Cub Cadet, Exmark, Scag and Wright. We can help you find a mower that fits your needs, add accessories, and keep it running with parts and repairs. When you need lawn care equipment, visit us at 4900 Molly Pitcher Highway in Chambersburg, PA. You can also order parts and accessories from us at www.shankslawn.com. We ship across the U.S. and Canada.