How to Compost Fall Leaves: Turn Autumn Leaves Into Garden Gold

Every October, the big sugar maple near our garden shed drops its leaves in what feels like a single weekend. One day the yard is green, and the next I’m scrunching through ankle-deep gold and wondering where I left the rake. I used to see that pile as a chore. Now I see it as free garden gold.

Fallen leaves are one of the best soil builders you’ll ever find, and they cost nothing. Here in zones 6 and 7, we get plenty of them. And, even though I live on a loblolly (timber) farm, I have plenty of deciduous trees like the maple, dogwoods, and beautiful redbuds to provide autumn leaves for the compost pile.  Here’s how to turn them into rich, crumbly compost.

Why Compost Fall Leaves?

Trees send their roots deep into the soil all summer, pulling up minerals and nutrients. Leaves change color in fall thanks to a combination of light and temperature changes, shutting down chlorophyll production to reveal the hidden gems underneath: the carotenoids, flavonoids, and other phytonutrients and plant pigments hidden by summer’s green. When the leaves fall, those nutrients come with them. Composting leaves returns them to your garden.

Finished leaf compost, often called leaf mold, does a lot of good:

• Improves soil structure. It loosens heavy clay and helps sandy soil hold water.
• Feeds earthworms and soil microbes. They do the work that keeps a garden healthy. Earthworms in the garden are a sign of soil health, and their castings add more nutrients into the soil. 
• Makes excellent mulch. It holds moisture and keeps weeds down, although be sure to keep as many seed pods (especially from redbuds, which are prolific!) out of the compost. Unless the pile heats up, the seeds will germinate.
• Saves money. You won’t need to buy as many bagged soil amendments, and you won’t need to bag leaves for the curb. 

How to Compost Fall Leaves

If you’ve never composted leaves or grass before, and you are new to building a compost pile, be sure to read my guide on how to build a compost pile first. You don’t need an expensive compost tumbler. You can stack bricks or cement blocks to make the form that you’ll fill with leaves to make compost, or you can use a mesh form or barrel to make compost. As long as air and water can get in, and excess water drain out, the leaves should decompose into compost.

Gather the Leaves

• Rake leaves from your lawn and garden beds. Dry leaves are lighter and easier to move, so pick a dry afternoon if you can.
• Most leaves compost beautifully. Maple, birch, ash, and fruit tree leaves are all good choices.
• Oak and beech leaves are slower to break down. Mix them with other leaves, or just be patient.
• Go easy on black walnut leaves. They contain a compound that can bother some plants. Mix them in with other materials and let them age well before using the finished compost.

Shred Them

If you can’t shred the leaves, don’t worry. It may just take a little more time for them to break down.

• Shred the leaves before composting. Whole leaves mat together and break down slowly, while shredded leaves can turn to compost in a fraction of the time. I don’t have a shredder, but my dad always used a shredder, and he made better compost than I do. It really helps the leaves break down into that desirable “black gold.” 
• Run the lawn mower over the pile. A mower with a bagging attachment makes this easy. Mowing leaves into small pieces also lets you collect them as you go. A bagging attachment can also suck up the leaves via your mower, making one less chore for you. 

Build the Pile

• Choose a spot. A wire bin, a pallet enclosure, or a corner of the yard will do. I have built piles with just stuff dumped on the ground, in a wire form, with a nice brick wall, and now with our cement block two-bin system. It all works. 
• Aim for a pile about three feet wide and three feet tall. It’s big enough to hold moisture and warm up, yet small enough to turn. Make sure air can circulate, and extra water can drain away, or you’ll get a nasty mush that can smell bad instead of sweet-smelling compost. 
• Add a little nitrogen. Leaves are “browns,” rich in carbon, so mix in a few handfuls of “greens” such as grass clippings, vegetable scraps, coffee grounds, or a shovelful of finished compost.
• Don’t have any greens? Don’t worry. Leaves will still break down. They just take longer. Adding kitchen scraps, such as potato, apple, and carrot peels, as well as any other plant material from the kitchen, like that lettuce that went limp or the tops celery, also helps. 

Keep It Damp

• Moisten the pile as you build it. Rainwater may be enough to keep it moist, depending on your part of the country. 
• Check it every so often. If the pile dries out, decomposition slows to a crawl, so give it a bit of water. During the winter, just leave it alone. In fall and spring, a sprinkle with a watering can or hose is fine if it hasn’t rained in over a week. 

Turn It Now and Then

• Turn the pile every few weeks with a shovel or a garden fork, whatever you have on hand. Move the outside material to the center to add air and help everything break down evenly.
• If you forget, it’s okay. Leaves are forgiving, and an unturned pile will still become compost. It just takes longer.

Be Patient

Finished leaf compost takes anywhere from three months to two years, depending on your climate and how much work you put in. A shredded, damp, turned pile finishes fastest. A pile of whole leaves left alone behind the shed takes its sweet time.

You’ll know it’s ready when it’s dark, crumbly, and smells like the woods after a rain.

The Easy Way: Bagged Leaf Mold

If you want the least work possible, try this method:

• Fill large trash bags with shredded, damp leaves.
• Poke a few holes in the sides for air.
• Tie the bags closed and tuck them behind the barn, the shed, or any out-of-the-way corner.
• Forget about them until next fall. When you open the bags, you’ll find dark, crumbly leaf mold ready to use.

How to Use Your Leaf Compost

• Mulch perennials, shrubs, and trees to hold in moisture and suppress weeds.
• Work it into vegetable and flower beds before planting to enrich the soil.
• Top-dress your lawn with a thin layer in spring.
• Mix it into potting soil for containers. Sift out any large pieces first.
• Spread a layer over bare garden soil in fall to protect it through winter.

A Few Extra Tips

• Don’t pack the pile down. Air is what the microbes need.
• Skip leaves with heavy fungal spots or disease. Good garden hygiene now prevents problems later.
• Save some leaves for later. Stash a bag or bin of dry leaves near your compost pile and add them throughout the year to balance your kitchen scraps.
• Use a few whole leaves as mulch right now. A light layer over your beds is a cozy winter blanket for the soil.

Fall leaves ask very little of a gardener, just a little raking and a little patience. Compost them this autumn, and your garden — and your spring self — will thank you.