Fall leaf collection is very peculiar here in Racine, Wisconsin. People rake or blow their leaves into rough piles in the street which sit there for days or weeks. At some point, a front-end loader may or may not come by to scoop the leaves into a garbage truck.
Nobody seems very certain of Racine’s leaf collection schedule. Our Solid Waste Division does post details of its Fall Leaf Collection system as a Word document (look near the bottom of their page), but our first pickup isn’t scheduled for another 11 days, and we’ve already had leaf piles in our street for at least that long.
In the meantime, the leaves are blown by the autumn winds. Cars either swerve to avoid the piles, or drive through them, scattering the leaves little by little. Back when it used to rain here, the leaves would either wash down to the storm sewer — potentially clogging it — or slowly break down into wet, molding mounds of matter, which is exactly what they’re supposed to do. They’re just not supposed to do it on concrete.
Autumn leaves, you see, are an important source of organic matter for soil.
In nature, where people do not rake them onto concrete and garbage trucks do not pick them up, leaves break down into the dirt. Dead leaves are basically what earthworms eat, and earthworms are incredibly beneficial to the soil.
Apart from the water-retentive fiber — without which our soil would be simply sand and clay — organic matter from leaves also provides an incredible regimen of nutrients to keep the soil healthy.
Remember the tomato blight of 2009? This past March, Mike McGrath, the host of the weekly public radio show You Bet Your Garden, spoke on NPR about how gardeners can prevent disease. Here is what he said (with my added bold letters):
And find a source of good yard waste compost. This is the world’s greatest soil amendment, disease preventer, and natural plant food. Compost that’s made from last year’s fall leaves contains every nutrient that we know of that plants need. And they can utilize these natural nutrients to fight disease with their own inner resources that chemically fed plants can’t utilize.
Even a corporation whose business is chemical plant food — The Scotts Miracle-Gro Company — advises, “Don’t rake those leaves. Mulch them into your lawn.”
I have found that, at least early on, my mulching mower has no trouble chopping our leaves into fine bits that will break down into the lawn if we ever get rain again.
Later, when the vast bulk of the fall leaves covers our grass, our lawn mower’s bag will get its only use all year. In these final few weeks, the mower is used to chop and collect the leaves, which are then spread from the bag over our various shrub borders and garden beds.
Some into the grass, plenty into the garden beds. The worms will eat these leaves, the perennials will be insulated by them, and the soil will be enriched and inoculated.
Why on earth would anyone want to rake these wonderful leaves into the street — or burn them, and pollute the air?
Update: Everything You Know About Composting is Wrong
Here’s Mike McGrath’s TEDx talk in Phoenixville, Pennsylvania on October 6th, 2012 about using nutrient-rich leaves as an ideal compost for all of your gardening needs.