If you have shade trees, you now have leaves. Thousands of leaves. You wake up one morning, and the neighbor is blowing his leaves onto your lawn. You don’t even own a maple tree, but there they are — his maple leaves on your lawn. What’s a gardener to do with all of those leaves?
The landfill certainly doesn’t want them. Your neighbor apparently doesn’t want them, either. And until now, you didn’t know that you wanted them.
Here are things you can do with those leaves — things that will better your life and your landscape.
▪ Get them off the grass. Those leaves will pack down, and in the process, they’ll trap moisture and warmth. They’ll stop airflow and cut off the sunshine to your lawn. Those are all bad things. Nothing much good happens when you shingle your lawn in old leaves.
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▪ Run them through the mower. It’s the next step in putting fallen leaves to work for you. They break down a lot quicker if they’re ground into small pieces. (Remember how much more efficiently you could get through the roll of Life Savers if you chewed them up? Surely I wasn’t the only kid who did that.)
The thing you may not realize is that the benefits old leaves provide to our plants happen while the leaves are decaying. The more steady the decay, the better the results. If you don’t have too many leaves, you can let them return to the ground. We’re talking mega-leaves here, where you wouldn’t be able to see the grass for the fluff of shredded foliage.
Fork in the road
Now you have to make a decision. Do you have some places where you want to use those shredded leaves now, or would you rather warehouse them as they “mature”?
▪ Use them as a mulch. Mulches are things we put on the surface of the soil to moderate the rates at which the soil’s temperature changes. Mulches slow splash, runoff and erosion, and they reduce or eliminate germinating weeds. Mulches look good.
Shredded tree leaves are outstanding mulches. Take them right out of the mower bag and spread them around, 3 or 4 inches deep. They’ll settle with the first few rainstorms, but because they’ve been shredded, they won’t pack and form an impenetrable layer. As they decay, they’ll add organic matter to the top surface of soil in your shrub and perennial beds.
▪ Use them as a neutral ground cover of bare soil. I have a couple of places way back in our landscape. They’re barely noticeable at best. I don’t want to plant living ground covers out there, but in the winter, they’re muddy. I take some of our shredded leaves and spread them over those areas. It doesn’t work on slopes where a heavy rain would quickly wash them away, but it’s a great way to put that organic matter and its nutrients back into the soil rather than sending it to the landfill.
▪ Layer the leaves into the compost. That’s the other way your journey can turn. It’s where you invest those leaves into becoming future soil amendments that can be turned into the ground. Most “fresh” sources of organic matter that have not yet been composted will decay too rapidly when mixed into the soil. In the process, the bacteria that are active in causing that decay will have tied up the available nitrogen so badly that the plants will be stunted and starved.
However, rather than being tilled immediately into the soil, those shredded leaves need to spend time in the compost. Build some type of decay-resistant enclosure out of concrete blocks, treated wood or just fence wire lined with polyethylene plastic.
Put 4 or 5 inches of the shredded leaves into the bin, then add 1 inch of garden soil, and additional inches of rotted manure, kitchen vegetable waste or other organic matter. Add one cup of high-nitrogen lawn food per cubic yard (3 feet by 3 feet by 3 feet) of compost. Use a spading fork with a reinforced handle to turn the pile every month. That will blend all the organic matter together. Keep it moist and warm all the while. A large, black plastic trash bag laid over the top of the pile will soak up the sun’s heat and hold in the moisture.
Are there any types of leaves that should not be included in the compost or used as garden mulches? My opinion is no, there are not. Oaks, walnuts and pecans, for example, are often said to contribute tannic acid that can retard growth of plants. While that may be the case, it argues a different point. The leaves wouldn’t be adding that much, and if it’s on top of the soil as a mulch, it’s not going to have much of an impact. If it’s composted for one to two years, any tannin is going to be dissipated. Plus, remember the recipe for good compost: use many types of organic matter. It’s a natural hedging of bets.
I live and garden in a pecan and oak forest. Half of the organic matter I work into my soils comes from composted oak and pecan foliage. In 38 years of doing this, I’ve never seen any sign of a problem.
How do you know when your compost is ready to use? Simple: It’s after you’ve turned and blended it several times, and it’s when the original sources of organic matter (grass clippings, shredded tree leaves, kitchen vegetable waste, etc.) are no longer recognizable as what they used to be in their former lives.