Do you think of falling autumn leaves that cover your lawn and driveway as an annoying nuisance that have to be raked up, stuffed into lawn bags and hauled to the curb? If so, think again. Think of them as money in the bank, a free amendment for your garden soil.
All you have to do is turn the red, yellow and gold colors of autumn into rich, dark leaf mold.
What is leaf mold?
Leaf mold is a form of compost that is created by letting leaves — just leaves, no other organic matter — decompose over a period of time. Leaf mold differs from garden compost in several ways.
For one, because of their dry, acidic and low-in-nitrogen nature, leaves decompose into leaf mold through the slow “cold” process of fungal breakdown. Garden compost, which is derived from a variety of organic material, is created by bacterial decomposition, which relies at least in part on heat buildup among compost ingredients.
For another, leaf mold and compost serve different purposes. While leaf mold doesn’t provide as many nutrients to the soil as compost, it greatly adds to soil structure, increases the ability of soil to retain water and provides a habitat for soil life, such as earthworms and beneficial bacteria.
Perhaps best of all, other than the cost of a black garbage bag and a few sore back muscles, leaf mold is free and ridiculously easy to make.
How to make leaf mold
Place a construction-grade black plastic bag over an empty garbage can.
Rake leaves and place them in the garbage bag. Shredding the leaves by running over them with a lawn mower will speed the decomposition process.
Compress the leaves to pack as many as possible into one bag. It may help to loosen the garbage bag from the rim of the garbage can several times to remove air pockets.
Pull the full bag of leaves from the garbage can, tie the bag closed leaving an opening to insert a hose and set the bag out of the way in a part of the yard or garden that gets rain.
Poke holes all over the bag's surface with a screwdriver, scissors, garden fork or other sharp implement to create entry holes for worms.
Insert a hose in the hole you left at the top of the bag and soak the leaves.
Six months later, turn the bags over.
The leaf mold should be broken down into flaky one-inch particles of a rich, dark brown color within 12 to 18 months. The time will vary by the climate in your part of the country. You’ll know they’re ready because the broken-down leaves will have the earthy smell of the forest floor after a rain shower.
How to use leaf mold
Leaf mold has several uses in perennial beds or in vegetable gardens.
It can be dug or turned into the soil between seasons, used as a top dressing or mulch or even mixed with water to create a “tea” that can be used for watering roots or as a foliar spray. It's also great to use in containers because of its ability to retain water.
If your black bags haven’t deteriorated, they can even be re-used when leaves with those beautiful fall colors begin dropping from the trees next fall.
Inset photo: Angela Renals