Making Leaf Mold

by Sadge, at Firesign Farm
I was out riding my bicycle around a quiet neighborhood of one-acre lots. As I rode past one house, with lots of lawn surrounded by big trees, an elderly couple was tossing puffy-full trash bags over their fence onto a huge pile on the side of the road. That looked like something I could use. I turned around and pedaled back to them.

"Are those leaves by any chance?" I asked. "May I have them?"

"Either you or the trash pickup, whichever gets here first," they replied.

"I'll be back with the truck. Oh, did you spray your trees with anything this year?"

Assured that the bags held only leaves, and that I'd be bringing no noxious chemicals back to my garden, I rode home smiling. Returning with the truck, I managed to get the entire pile, at least 25 big black trash bags, into the truck bed, piling them up, mashing and wedging bags in against the sides so as not to lose any as I drove home. What a treasure!

leaf mold bin in foreground, Aries & compost bin beyond

We're already making compost with our garden cleanup, the leaves from our trees, and the manure from cleaning out the chicken coop. I had something else in mind for these leaves - a batch of leaf mold.

Leaf mold is just leaves - piled up and left to decompose. To help them break down faster, we ran them through the shredder first. I made a round bin, about 3' tall and 3' across (it's best to have a pile at least 3' x 3'), with a length of wire fencing, lining it with some of the trash bags to keep the bits of leaves from falling through. First raking, then closing up the circle and shoveling, we filled the bin to the top. Using a small step ladder, I got into the bin, stomping round and round, packing the leaves down as Aries kept shoveling. With a bit of work, we got an entire piled-high truckload of leaves packed into the bin.

I got the hose, and soaked it all down, until water just started to run out the bottom. I live in the high desert, so to keep the leaves from drying out I covered them with more of the trash bags weighed down with bit of carpet and a slab of wood (winter storms can come through here with 60 mph winds). Last item was then to use a pitchfork to poke small holes in the plastic lining the bin. Some oxygen is necessary for the decomposition process.

Unlike the pathogen and weed seed killing heat of a properly made compost pile, making leaf mold is a cold process. Even so, a week later, the contents of my bin, six inches below the surface, pegged out a 125F thermometer. Left alone, leaf mold bins can take up to three years to break down to a dark, crumbly texture - a much slower process than composting. But by shredding the leaves and wetting them down well this bin might be ready by next summer.. And leaf mold, being made of only leaves, doesn't have the multitude of minerals and plant nutrients of compost either. But dug into a garden bed or used as mulch, it's great at retaining water. That's a necessity for my sandy soil and hot, dry growing season, but it can also soak up and hold the water in too-wet soils as well. It's also a great additive to a container potting mix. If you have or can get the leaves, have the room for a bin or two, and the time to let it break down, leaf mold can be a valuable addition to any garden.