This could be you, but you're too busy raking (Patrick/Flickr)

It's autumn! The air is crisp, the PSL is flowing, and decorative gourd season is upon us.

For those of us cursed with lawns, fall also means hours of backbreaking work raking leaves into piles, stuffing them in bags, and hauling them off to who-knows-where just in time for the neighbor's leaves to blow onto our lawns, starting the process anew.

It doesn't have to be that way.

According to Sam Bauer, a turf grass researcher at the University of Minnesota, the best thing to do with your leaves may be to forget about raking and bagging, and simply go over them with a lawnmower from time to time.

"The leaves have organic matter in them, you're adding good organic matter to your soil when you're not picking them up," Bauer said in an interview.

You don't need any special equipment to do this -- you can just run the leaves over with your regular mower. If your lawnmower has a side discharge outlet, where a bag or chute usually goes, just close it up, Bauer says. "What that does is it keeps the leaves in the housing of the mower and they get chopped up much more finely."

If you want to get really fancy about it, you can buy a specialized mulching blade for your mower that'll chop them up even more finely.

If you take this approach, the benefits to your lawn are two-fold. First, all the organic material adds good nutrients to your soil, which will help your grass grow better next year. Bauer says he sometimes hears from people worried that too much leaf material will alter their soil chemistry in a bad way. "To me, none of that is valid," he said. He's done some research into this, and found no evidence that too much leaf mulch will alter your soil in a way that hurts your grass.

The other great thing mulching does: It suppresses weeds. Bauer points to experiments showing that leaf mulch reduced the appearance of dandelions by up to 84 percent the following season. Take a look:


Kowalewski et. al., 2010

So if mulching is so good, and so easy, why does it seem like everyone's default is to do it the hard way with a rake and some bags every weekend from September to Thanksgiving? Bauer doesn't know, but he points out that when it comes to lawn care, a lot of people still do things out of habit regardless of whether they're actually useful.

"Everyone thinks that your lawn needs to be watered every other day, too," he said (it doesn't).

But, Bauer cautions, there's a limit: if your lawn is just completely plastered in leaves, you may need to remove some before you mulch the rest. But how much is too much?

I sent Bauer photos of different leaf densities on my own lawn, labeled A through D below, to see how he would deal with them.


Here's what he said:

A: You could allow this many leaves to cover the lawn over winter, but they can be easily mulched before that.
B: This would be an easy amount to mulch.
C: This level could be mulched with a good mower. Consider mulching blades and close the side discharge.
D: This is too many leaves to mulch all at once. Consider removing 25-50 percent and mulching the rest.  Or mulching first and raking up the excess.

So if your lawn looks like figure D, does this mean you're still stuck with the ol' rake-and-bag? Not exactly. If you've got a garden, one thing you can do is just dump your excess leaves there and let them compost on top of the soil over the winter.

It doesn't matter how many leaves you unload on the garden, Bauer says, so long as you let them decompose over the winter before tilling them under in the spring. "For gardens, in a lot of cases, it's almost always a good thing to be adding organic matter. "

And if you want to go the mower-mulching route this fall, you may need to get out there with your mower more often than you were when you were just cutting grass in the summer. If the leaves are falling fast, you may need to be out there once, even twice a week to keep them manageable.

But for the average homeowner with the average amount of leaf litter, the periodic pass with the mower should do the trick, and it brings the added benefit of being good for your grass, bad for your weeds, and probably a lot easier to deal with than raking all fall.

For homeowners, there's nothing better than when the optimal solution is also the lazy one.