From the weekend, one of those odd collisions of news that occur from time to time:
- In Minneapolis, the city is extending its yard-waste pickup program for a final week, through Saturday, because leaves have been falling so much later than normal this year.
- Meanwhile, in the New York City suburbs, local governments are campaigning aggressively against the raking and bagging of leaves as a practice that’s bad for municipal budgets, not to mention homeowners’ lawns and backs.
Residents of Westchester County are being urged to simply run over the leaves with a lawnmower, chopping them into fine mulch that can be left where it falls — or, alternatively, using a bagging attachment to gather the shreds for composting in a bin or heap behind the garage.
It was out of sheer laziness, I admit, that the lawnmower method was my standard leaf-management practice during most of my years living in the city, for there is no chore I loathe more than packaging leaves for pickup.
Typically I used the bagger and piled its gathered contents onto raised garden beds, covering them with black plastic to kill any pests and speed the leaves’ conversion into fresh black loam for turning into the soil come spring.
Who knew I could have done my sad little lawn a favor by just leaving the shredded leaves in place?
Shredded leaves as weed fighters
Sam Bauer did. He teaches on turf and lawn matters in the University of Minnesota Extension program, and he told me that for well over a decade he and his colleagues have been preaching to homeowners on the many benefits of giving up the rake and making use of free turf builders falling from the trees.
Not only are chopped leaves good organic fertilizer, he said, there’s research suggesting that certain types of leaves — black walnut and maple, for example — may suppress dandelions.
And the leaves of the honey locust — the most annoying material I had to manage on my Minneapolis lot, because of the quantity and cornflake size — not only need no shredding but deliver nitrogen to turf in especially high amounts.
Despite such obvious benefits, Bauer said he is aware of no local governments in the Twin Cities metro that are following the kind of strategy that Westchester officials are pressing to let the leaves stay put.
Their reasons, according to the New York Times, have to do as much with cost to taxpayers, water quality and public safety as benefit to soils and lawns:
Westchester spends $3.5 million a year on private contractors who haul away leaves in tractor-trailers and bring them to commercial composting sites in places like Orange County, N.Y., and Connecticut. ….
[T]he county pays a private hauler about $40 for every ton of leaves that it takes away. Municipalities that provide leaf pickup service pay the county $15 a ton. So some county residents ultimately foot the bill through both municipal and county taxes.
County officials say mulching leaves in place not only improves soil quality, but also has other environmental and safety benefits for communities. Piles of leaves left at the curb can clog storm drains; the nitrogen and phosphorous leaching from decomposing leaves heaped by the street can also more easily enter the drains and harm local rivers. Additionally, leaf piles constrict already narrow streets and can conceal children.
The costs to Minneapolis
As it happens, costs in Minneapolis may be fairly comparable. Heidi Hamilton, the city’s deputy director of public works, said the city budget for yard-waste collection is $2.87 million this year. On a per-ton basis, the cost to collect the leaves and haul them to one of two mass composting operations averages $45.
There is no way to determine how much of that expenditure goes just for leaves and how much for brush and other yard waste, although common sense and observation suggest that bagged leaves must account for the larger share by far.
And I was interested to learn that, in recent years, the leaf-disposal cost has increased substantially during periods when the Minnesota Department of Agriculture prohibits movement of certain tree products in an effort to contain the emerald ash borer.
Hamilton explained that the movement restrictions apply to brush and branches over an inch in diameter, but “because we don’t really know what else might be in the bag with leaves, we have to put it all through the shredder. Every single bag.”
(In St. Paul, by the way, leaves and other yard waste are banned from your normal trash pickup. So you’ll have to haul the bags yourself, or hire someone to do it for you — more good reasons to compost.)
Hamilton checked with colleagues and learned that for a short while, more than 10 years ago, the city did some public-education work aimed at getting more people to chop the fallen foliage with lawnmowers and leave it where it fell.
No such efforts are under consideration now, she said, “but you’ve got me thinking.”
If I’ve got you thinking about how to handle your last leaves of the season, Sam Bauer would like you to be sure you’re doing things right.
Tips for the convert
First of all, with snow approaching, you don’t want to leave your lawn covered with too thick a layer of leaf matter no matter how finely chopped.
“You want to be able to see grass coming up through the mulch,’ he said, “with no more than 10 or 20 percent covered.”
That might require several passes with the mower, and a special mulching blade can speed the process but isn’t really necessary.
“The main thing is, when the snow comes, you don’t want leaves sitting on the canopy” — what turf guys call the tip-top portion of the grass —because that just promotes winter kill, mold, moles and other pests.
So if you haven’t been keeping up with your leaves and have a lot to deal with in the waning days, Bauer advises gathering them for a compost pile — either with the mower and bag attachment or, sigh, a rake. (Or, grrr, a leaf blower.)
Then resolve to do better next year.
“If you’re going to be mulching all your leaves into the lawn, you need to be mowing more often than the grass itself needs,” he said. “At least a couple of times a week, and maybe more if the leaves get heavy. So it takes a little more time than normal mowing.”
But still better than raking and bagging, right?
“Oh, way better,” he said. “And it’s a huge benefit not just to your lawn, but to the whole environment.”
Not to mention the city’s waste-disposal budget.
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For more information about composting leaves, either in place on the lawn or in a bin or pile, start with the U of M Extension page on the topic. For more information on Minneapolis policy and practices regarding yard waste, see this Public Works Department page.