A Constant Battle: Mulching Mowers

Five to 10 years ago, on a mission to save landfill capacity, the Environmental Protection Agency made yard waste its No. 1 target for landfill bans.

Since grass clippings made up 20.1 percent of all solid landfill waste burned by Americans annually, according to the Professional Lawn Care Association of America, grass clippings were an easy target, being second only to paper and paper board products at 35.6 percent. By 1993, eight states had effectively banned grass and tree trimmings from landfills.

Programs encouraging the recycling of grass clippings began nationwide as PLCAA started Grasscycling: Today’s Turf – Tomorrow’s Earth, a national public awareness campaign encouraging grasscycling, the environmental practice of naturally recycling grass clippings by leaving them on the lawn when mowing.

Commercial mower manufacturers addressed this environmental concern and industry trend by producing machines with mulching decks that would tear up grass blades into tiny pieces and disperse them back into the grass.

"Some people even predicted an end to the production of grass catchers," pronounced Bob Walker, president, Walker Mfg., Fort Collins, Colo. "But that never occurred because mulching mowers didn’t work as well as everybody thought they would."

While mulching mowers worked fine for contractors in dry, slow-growing grass conditions, others complained of clumping grass and an unattractive appearance, wasted time spent cleaning out sticky grass from mulching mower decks and how using a mulching mower once each week couldn’t keep up with spring’s rapidly growing grasses and may have been contributing to an increase in weeds and pests.

THE GREEN CULPRIT. To be practical for a landscape contractor, Walker explained, mulching mowers need to work well in all weather conditions, especially during spring’s busy season.

"Grass itself is the key obstacle with mulching mowers," Walker explained. "Grass is not a predictable product to mow. In the spring, there is a lot of juice inside the plant and it gets real sticky and can clog up a mower deck. It doesn’t matter what methods are used to make the grass dance around repeatedly through the blades of a mower deck. If grass is sticky, it doesn’t dance very well and will cling underneath the deck and then the deck will have to be cleaned off, which amounts to extra time and labor for contractors."

The biggest drawback in having a mulching mower is altering how it’s used based on the season, said George Kotalic, president, Kotalic Landscaping, Huntington, W.V. For Kotalic, the grass is too high and too wet in March, April and May, but he still thinks mulching mowers +save him catching time.

"I would rather double mow a yard with a mulching mower than pick up grass clippings," Kotalic admitted. "I just keep my mulching blades sharp so I can get the most out of them and mow my clients’ yards twice per visit during the spring."

Other contractors, such as Scott Evans, president, Scott & Co., Bay City, Texas, catch grass in the spring and then switch to mulching in the summer because the mowers handle the drier, less sticky and slower growing grass better. Overall, however, Evans still believes that catching provides the highest quality appearance to a customer’s lawn.

Mike Ford, maintenance operations manager, BP Landscaping, Grass Valley, Calif., said his company doesn’t do much mulching because in the spring he can’t handle the large volumes of grass that pile on top of the lawn.

"Cut grass doesn’t decompose fast enough to leave a quality appearance," Ford said. "In some instances, this has even caused thatch layers to build up.

"And last year," Ford continued, "we had rain here into July and mulching mowers don’t do well on wet turf. Mulching technology on mowers just isn’t to the point yet where we could effectively use and manage the equipment."

Wet grass naturally clumps until sufficient moisture has been removed from it, pointed out Dane Scag, president of Great Dane Power Equipment, Elm Grove, Wis., and grass moisture is extremely variable from the morning to the afternoon.

"No matter what method is used to disperse grass evenly, when the grass is wet it’s always going to clump," Scag noted.

Joe Reynolds, manager of the lawn care division at Black Diamond Lawn Care, Toledo, Ohio, shared his concerns with the mulching mower reintroducing disease pathogens and pest eggs into the grass and soil.

"Over the last decade in this area, I’ve noticed a big change," Reynolds said, pointing to increases in chickweed, red thread and crabgrass. "And it all points back to the advent of the mulching mower.

"For example," Reynolds continued. "If there are 10 million crabgrass seeds on the ground and you catch 9 million then there’s only 1 million seeds left. But if you mulch,

there are always 10 million seeds left there. And if I’m using a preemergent, which is typically 90 percent effective, I would rather prevent 90 percent of 1 million weed seeds than 90 percent of 10 million weed seeds."

In addition to grass conditions and seasons, location makes a difference in a mulching mower’s performance, recognized Ken Raney, advertising manager, Excel Industries, Hesston, Kan.

"In Florida, contractors cut their grasses at a 4-inch height, which means they have an additional 1- or 1½-inch layer of grass to mulch down into," Raney said.

While Florida contractors generally favor mulching mowers, Walker agreed, those in the Northeast don’t get the results they desire with mulching mowers because of their cool-season grasses and heavy leaf fall in the autumn.

"Arizona or places that overseed with ryegrass are also poor locations for mulching mowers," Walker said. "Ryegrass is terrible to work with when it’s new because it’s so juicy and tender. It’s hard to do a good job cutting it and dispersing the clippings when all it does is turn into green mush."

THE ALTERNATIVES. If landscape contractors aren’t using mulching mowers, they are either using side discharge mowers or mowers with catching features attached, Walker said.

Approximately 75 percent of Raney’s customers are purchasing catching mowers over mulching mowers in certain models.

If used properly, Walker said side discharge mowers are a good alternative to mulching mowers.

"On some properties, using a side discharge mower isn’t a disadvantage when done correctly and neatly," he explained. "But if the property has a lot of sidewalks and pedestrian traffic, then a contractor is better off mulching to save time having to use a blower to clean up the grass clippings."

When it comes to catching, Ford and Evans said they don’t charge to haul away their customers’ grass, and they don’t take the clippings to a landfill. Evans’ company composts in-house and they mulch the grass clippings themselves and then resell it.

Ford also composts caught grass clippings, but he doesn’t charge his customers for the mulch later. He either gives it away to people who are doing composting or he uses it to take care of weed problems.

"Star thistle covers about 10 percent of California," Ford pointed out. "It’s a most disturbing and bothersome weed. Mulching over them, it smothers them out as opposed to using an herbicide that hasn’t proven as effective."

This saves Ford the cost of taking the grass clippings to a landfill and his environmentally conscious customers like the fact that he recycles.

Tim Suter, sales manager, FloraLandscape, Toledo, Ohio, said his company subcontracts the mulching of excess spring grass and fall leaves. The work costs about $8 per cubic yard. The company then collects the mulch and keeps it in accessible rows on an extra acre of land.

"When you bag clippings and take them to a landfill, it costs $7 or $8 per cubic yard in Toledo plus the cost of drive time to and from the landfill," Suter explained. "When we subcontract the grass for mulching, we pay about the same cost as a landfill charges and the cost of having the additional acreage to take care of the mulch. The difference is that in the end we have a sellable product."

ATTEMPTING A SOLUTION. Some mower manufacturers have attempted different machine designs in an attempt to improve the mulching mower.

Bush Hog developed a tractor-pulled mulching deck with two sets of counter rotating blades – one moving clockwise, the other moving counterclockwise, which is designed to cut the grass up into finer pieces for mulching, said Bob Moore, vice president of sales and marketing, Bush Hog, Selma, Ala.

And Excel created an upper deck above the middle blade of the mower to hold the grass above the deck longer so that it gets another chance to run through the three blades and result in tinier pieces, according to Raney.

Yet most mower manufacturers agree that when a contractor uses a mulching mower – no matter what the design, the condition of the grass will always make a difference in its performance.

"Even with our new system, there are still situations where a contractor won’t be able to mulch," Raney admitted.

Even though manufacturers are trying to develop something new, most manufacturers have exhausted their current ideas and are still in the stages of research.

"I don’t expect any real breakthroughs soon," Walker remarked. "I don’t think there is any new mulching mower technology on the horizon – at least nothing that will make sales jump 20 to 50 percent."

The author is Assistant Editor of Lawn & Landscape magazine.