When I was a kid, one of the things we did every autumn was to help rake up huge piles of leaves, and then run and jump in them. The younger children threw themselves into the piles, while the older ones turned leaf-pile jumping into a broad-jump type event. It was good, dirty fun that lasted until the leaves lost their loft and were hauled off to the compost pile.
We didn't know it at the time, but all our jumping helped prepare the leaves for composting. When whole leaves are broken into smaller pieces, they leach out their tannins more readily than whole leaves, which transforms them into a suitable lunch for varying strains of fungi. These days I use a mower to coarsely shred my leaves, which I then use as winter mulch in the vegetable garden.
Indeed, the mixture of chopped leaves and end-of-the-season grass clippings I can collect with my mower's bagging attachment is the best mulch I have found for covering newly planted beds of garlic.
In the more wooded parts of my yard it is more practical to rake whole leaves into a bin for later use in compost or as mulch, and sometimes friends offer me plump bags of whole leaves. Setting up a temporary holding bin for composting leaves using stakes and plastic fencing takes about ten minutes, and some kind of enclosure is required to keep the leaves from blowing about.
At first I make no attempt to moisten my gathered leaves, because dry leaves break into pieces more readily than wet ones. Thin leaves like those from dogwoods or poplars crumble like potato chips when they are dry, and thicker oak leaves crack into pieces. I stomp through the piles each time I add more leaves to crush them up a bit, and then wait for winter rains to gradually wet down the leaves.
I am often asked about speeding up the leaf composting process by adding either fertiliser, as a nitrogen source, or a microbial compost starter. Neither are good ideas. Research on the biology of leaf decomposition has shown that the specific strains of fungi needed to start the rotting process are on the leaves before they fall from the trees. These fungi need only moisture and time to do their work, and might be set back by the introduction of alien microorganisms or chemical changes in their environment. Once you hoard a quantity of leaves and have them contained, you can let them sit there until you find a good use for them.
Leaf Mulch for Vegetables
By spring my collected leaves have begun to soften, but they are still in clumps that smell like rotting leaves. I often snake a soaker hose around the pile to provide moisture, but then proceed to use the half-rotted leaves as vegetable garden mulch as the need arises. Leaf mulch keeps the soil cool while blocking light to weeds, and several vegetables including bulb onions, pumpkins and potatoes have shown higher yields when their root zones are covered with a thick blanket of leaf mulch. Young fruit trees respond well to leaf mulch, too, by showing faster growth and better use of soil nutrients.
If I were more patient I might make a batch of true leaf mold, which takes two years in my climate. An ideal substitute for peat moss, leaf mold does a great job of retaining moisture and suppressing diseases in potting compost mixes, and it dramatically lightens up soil when dug into a garden bed. I used to have lots of it, thanks to neighbours who dumped their leaves in the woods every fall and forgot about them -- after letting the neighbourhood kids jump in the piles first.
By Barbara Pleasant