There’s autumn gold in your garden, and not just Ginkgo ‘Autumn Gold’. If you have deciduous trees like Ginkgo, they offer opportunities for bountiful harvest. As leaves color up in fall, you get to observe one of Nature’s most efficient ways to nuture itself. Those colorful changes signal the transfer of vital nutrients back into branches, trunks, and ultimately, roots. When the leaves finally drop, they deliver essential organic matter. Harvest those leaves and pile them up to capture their riches for your garden. The leaf harvest can provide mulch, organic fertilizer, and the best soil conditioner money can’t buy.
Perhaps the easiest way to turn leaves into gardeners’ gold is to start a compost pile. This simple process relies on natural decomposition combined with your efforts to speed it up. As leaves rot, they go through predictable stages, each with its own value. It’s easy to get the microorganisms going by sprinkling an organic nitrogen (such as cottonseed meal) in the leaf pile as you build it. They quickly turn the pile to leaf mold, which looks like very old, dark leaves that stick together a bit. Next, with a bit more time, leaf mold becomes compost, where the individual leaves are unrecognizable in the mass. Left alone for years, compost becomes humus, a rich dark dense material found naturally in old woodlands.
Several factors determine whether compost takes three months or a yer to make: temperature, moisture, oxygen, and the ratio of green material to brown in the mix. The growing season’s natural warmth makes decomposition happen. But inside the compost, temperatures routinely top one hundred degrees as the microorganisms digest their dinner. Piling up the leaves accelerates their demise, as does moisture. The best piles stay moderately damp; usually rain will be sufficient. Turning the pile once a month really accelerates composting. One good way is to have two bins and dump the pile into one this month, then the other the next time you turn. Leaves alone will rot but adding lawn clippings and kitchen waste including vegetable trimmings, coffee grounds, and eggshells will make it go faster and will also increase the nutrient value of the end product. Most gardeners agree that one third green to two thirds brown works best.
Buy a compost maker or build a pile out behind the shrubs, but harvest your leaves this fall. You’ll be glad all year that you did.
This is the unedited version of an article that appeared in Garden Almanac, a publication of GroGroup.