Turning Over a New Leaf

Glorious Autumn! Keat's season of mists and mellow fruitfulness. It is also (alas) the season of the rake. It seems that you spend the better part of your precious weekends just raking up leaves. And just when you have gotten them under control, along comes a brisk gust of wind, a sprinkling of rain, and your lawn is covered all over again. Groan! Time to drag out the rake once more.

Here is a solution to simplify your fall and improve the long-term health and vigor of your lawn, trees, and garden beds:

Mulch ado about leaves.
There are a large number of expensive, awkward, and sometimes useful products being hawked to suck up your leaves and turn them into mulch. There are blower-vacs which blow leaves into a pile which you can then suck up and shred. There are chipper-shredders with elephant trunks that also allow you to suck up and shred leaves, although you have to rake them into piles first. And lawn jockeys with disposable incomes can check out the over $1,200 self-propelled machines which act like gas-powered vacuum cleaners on your lawn (watch out for small pets).

Mower for less.
These contraptions may not be the solution for you. However, if you are like most homeowners, you may not have realized that your lawn mower is already a deluxe leaf mulcher in its own right. And perhaps the easiest way to deal with leaves is to mow them right back into the lawn itself. Forget back-breaking raking and bagging!

Please note that mower-mulching works best when leaves are relatively dry and are no more than one inch deep. Deeper "drifts" might need to be partially raked first -- or plan to run back and forth over the leaves several times. And do not worry if your model is not a dedicated mulching mower, any type of mower will do.

Start your do-it-yourself "mulchinator" by setting the mower to a normal three-inch height. Remove bagging attachments and block off the discharge chute on a rear-discharge machine. Then run your mower over the lawn while walking slowly, giving the mower blades plenty of time to shred up the leaves.

If your mower has a side discharge chute, you will probably want to start on the outside perimeter of your lawn and start mowing inward. This will keep the leaf-bits on the lawn, and even allow you to mow over them a few more times. Of course, some folks like to "blow" shredded leaves into ground cover areas, under foundation plantings, or into wooded areas, adding to the organic content of soils there, which is another option.

If your first pass over the lawn has left a significant quantity of whole leaves, go back over the leaves while mowing at a right angle to the first cut, perhaps walking even more slowly. Leaves take more work than grass, especially if they are somewhat damp.

Stay out of the gutter!
It is important not to blow whole or shredded leaves into streets, storm drains, or nearby streams. Those innocent-looking particles can create problems for sensitive aquatic life by suffocating plants, fish eggs, and insect larvae, clouding the water, tying up oxygen, and altering the stream's pH (increasing toxic acidity). And that is also why you should never rake leaves into the street or gutter: leaf leachate always ends up in your neighborhood stream.

Too many leaves?
The swirling mass of leaves may seem daunting at first, but the final particle size will be one-tenth of the original leaf. This will make it easily digestible by worms and bacteria. Skeptics often voice a concern that shredding leaves into turf areas will overwhelm and kill their lawn. Not at all! In fact, research at the Rodale Institute in Pennsylvania found that earthworms will actually drag a one-inch deep layer of organic matter into their burrows in just a few months, loosening and enriching your soil, and feeding the roots of your lawn for free.

Numerically, while you may imagine that all of those leaves will add up to far too much organic matter for your lawn, the fact is that 30 tall paper bags full of leaves, once shredded, will break down within a season to about one cubic yard of leaf mold or compost. Applied to your lawn as a topdressing, you would only be able to cover about 48 square feet (a six foot by eight foot patch). In fact, to topdress a lawn properly, most savvy gardeners have to import tons of commercial compost above and beyond the compost they make at home! Fear not: you will never have too many leaves or too much organic matter!

Your lawn needs leaves.
For decades, homeowners have bagged their grass clippings and leaves and sent them off to a landfill. And lawn chemical salespeople successfully and profitably sold the idea that healthy lawns needed bimonthly fertilizer and pesticide applications. Times have fortunately changed. The fact is that lawns and gardens can be maintained organically, for the most part, and without toxic inputs, just by recycling the natural materials already in place. When you bag up your clippings and leaves, you are short-circuiting the natural recycling process.

Think of the cycle this way: tree roots absorb water, minerals, and a host of nutrients from the soil. These materials are used to add girth to the tree trunk and boughs, set forth new branches, grow more roots, and grow leaves, flowers, and fruits or seeds. In a natural setting, such as a forest or woodlot, leaves, small twigs, blossoms, and fruits drop to the ground and slowly decompose, returning all of the original organic building blocks to the soil for future use.

What happens when you bag up leaves? How is that organic matter going to get back to the soil for the tree to use in coming years? You may think that by fertilizing your lawn you are returning everything the tree needs. Wrong! Of the more than one dozen major and minor nutrients that plants need to grow, how many are in your bag of fertilizer? And what about the organic matter that creates humus, the very soul of soil itself?

Bagging leaves and grass is equivalent to strip mining. The minerals, nutrients, and organic matter are continually stripped away year after year. Eventually, without those vital materials, your trees, your garden, and your lawn will start to suffer. It is time to undo this damage by getting that organic matter back into the soil. And you can easily start just by mowing your leaves into your lawn.

It's in the bagger!
There are other options and uses for some of your shredded leaves. For example, if your mower does have a bagging attachment, you might want to take the shredded material and start using it to mulch some of your trees and shrubs. This is also true for gardeners with some of the fancier shredding equipment. Apply up to four inches deep, and your mulch layer will also act as a blanket to prevent frost upheaval in planting beds, which is especially damaging to bulbs, tuberous flowers, and some half-hardy perennials. You will also be feeding and protecting your plants and preventing weed growth for almost a full year.

A compost pile or bin is another excellent half-way point for shredded leaves. Those smaller leaf particles break down in less than half the time of whole leaves, and you can fit a prodigious quantity of shredded leaves into your bin. Also, if you find that you are cutting some grass while shredding leaves, you are probably creating the perfect blend of carbon and nitrogen-rich materials to ensure a hot, fast-working compost pile.

Recommended chores.
Mulching leaves into lawns is just the first step toward a naturally healthy lawn and environment. You should also consider aerating your lawn by either renting a core-aerating machine (about $70) or hiring a lawn care firm ($75 and up depending on overall lawn size). Aerating breathes life into compacted soils and helps organic matter filter deeper into subsoils and root zones. You should also test your soil with a kit from your county or municipality's local Cooperative Extension Service (costs are about ten dollars) to determine proper nutrient application rates. Your soil test will also indicate the type and quantity of lime your lawn needs; local soils are naturally acidic. And don't forget: fall is the only beneficial time to consider feeding your lawn -- only use a slow-release or organic nutrient source to feed the soil and your lawn's roots all winter long.

Copyright 2010, Joseph M. Keyser