What to do with all those autumn leaves?
According to Sam Bauer, turf specialist with the University of MN Extension Services, “It’s a misconception that leaves need to be raked, bagged and hauled away.”
In natural ecosystems, no one is doing anything with the leaves that fall. They land where they land, they decompose, and the process is essential to building healthy soils.
“The main reason that people haul their leaves away in the fall is that it’s what they’re used to doing,” Bauer said.
Bauer recommends making leaf mulching part of a fall lawn care regimen. “Mulching fallen leaves into the lawn is advantageous, so long as about 75% of the grass canopy is left visible,” he said. In other words, you want to see more green than brown. There’s no need to worry about snow mold. If you stick with Bauer’s recommendation, air circulation will be more than adequate.
Grass should be mowed and watered well into the fall. Just leave the leaves and mow right over them, either with your regular lawn mower (it will take a few extra passes) or with deeper serrated mulching blades. Mulching blades can be purchased for any lawn mower.
When mowing, remove whatever container would usually capture the grass clippings. Leave the cut grass and chopped-up leaves to rest on the lawn surface. They’ll settle into the lawn, providing some nutrients and organic matter for the soil below.
Leaf mold is “black gold”
What to do if you have more leaves than your lawn can absorb? Leaf mold may not sound pretty, but to gardeners it’s nothing short of “black gold.” There are a couple of ways to create it, the easiest being to make a pile of leaves, either contained or not contained, about 3’ by 3’. Let the leaves sit, adding water periodically, and within 6-10 months, they’ll have decomposed. By keeping the pile moist, decomposition will happen faster. Shredded leaves will also decompose faster than un-shredded ones.
The result will be leaf mold, a dark, rich mulch that is arguably the best soil amendment around. While leaf mold doesn’t provide the nutrients of regular compost, it does greatly improve soil structure, texture and water holding capacity. Leaf mold helps loosen heavy soils and adds heft to sandy soils. It can hold several hundred times its weight in water, and helps create a healthy ecosystem for beneficial insects.
While it almost sounds too good to be true, consider this. Soils amended with leaf mold may approach the poetic phrase,”well-drained and evenly moist,” so often read about in garden magazines but rarely seen in real life. In our work as gardeners, this is important! It’s as much about growing good soil as it is about growing good plants.
Don’t have a compost bin or container to make leaf mold in? No problem. Fill your compostable yard waste bags and, instead of having them hauled, or hauling them away, store them on the side of your house. Moisten the contents periodically and, by spring, bags and leaves should have decomposed into a dark brown to black, aromatic and crumbly leaf mold. Work 2-4” of leaf mold into the top 6” of garden soil in the spring, or ring the periphery of existing perennials with a top dressing.
Another great option for surplus leaves is to rake them loosely onto garden beds. While snow is an excellent insulator, it comes and goes—leaving perennials vulnerable when the temps dive down.
One important place to rake
The place to make sure you have raked meticulously is along your street. According to Sue Rich, volunteer coordinator with Friends of the Mississippi River, “This is where leaves actually become pollutants. As they break down, they release their nutrients. When allowed to wash into the storm sewer system, it’s like throwing down hands full of fertilizer. The excess nutrients encourage algae growth in rivers and lakes, which ultimately deprives fish and aquatic plants of oxygen.”
There are many small ways each of us can make a difference in caring for the natural world. Consider adopting the storm drain near your house or at the end of your alley, and commit to keeping it free of leaves and other organic material.
If none of these options for dealing with fall leaves appeal to you, remember that state law now requires everyone in the metro area to use biodegradable bags for yard waste. The bags will be picked up on trash day, and should be set out for pick-up by 6am. The City collects approximately 6,000-8,000 tons of yard waste annually, which is ground up and made available as compost eventually. Yard waste removal will continue this year through Nov. 16.
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