Save money and help the environment by using autumn leaves in the garden
“Tools of many kinds, and well chosen, are one of the joys of a garden.”
— Liberty Hyde Bailey, author of “Garden-Making,” 1898
Liberty Hyde Bailey (1858-1954) is called the father of modern horticulture because he was devoted to bringing science and technology to the study of gardens and gardening. He was one of the pioneers of the agricultural extension services and the nature study movement, and he co-founded the American Society of Horticultural Sciences.
In his book, “Garden-Making,” Bailey painstakingly describes how to prepare the home landscape for growing ornamental plants and food crops. He goes into great detail about the tools gardeners need for planting, weeding and other tasks.
Bailey notes, “If one puts his personal choice into the securing of plants for a garden, so should he discriminate in the choice of hand tools, to secure those that are light, trim, well made and precisely adapted to the work to be accomplished. A case of neat garden tools ought to be a great joy to a gardener.”
A collection of Bailey’s book chapters, essays and poems, called “The Liberty Hyde Bailey Gardener’s Companion,” was published in 2019 and, in my opinion, deserves a place on every gardener’s bookshelf.
In 2020, Nigel Palmer published a book called “The Regenerative Grower’s Guide to Garden Amendments,” in which he advocates new ideas about sustainable, regenerative garden tools. According to Palmer, “In the old garden model, rototillers, shovels, wheelbarrows and hoses are the essential tools that come to mind. But in the new garden model, the emphasis is on tools that directly affect the soil ecosystem and plant health, including water, mineral and biological amendments, compost, cover crops, mulches and weeds.”
Although Palmer’s perspective about garden tools is very different from Bailey’s, I think the father of horticulture would have appreciated Palmer’s recommendation for gardeners to analyze garden soil and then concoct specific organic amendments based on the results.
One of the soil amendments Palmer suggests is leaf mold. Despite sounding like something gardeners would not want anywhere near their plants, leaf mold is not a fungus; it is fertile organic matter produced from decomposed tree and shrub leaves.
When Jerry and I bought our east Medford property 10 years ago, there was a fenced-off section at the bottom of the backyard with a sugar maple tree in the middle of it. Fallen leaves from the tree had collected inside the fenced area for years, and the bottom of the leaf pile yielded magnificent leaf mold that we mixed in with soil to make our garden beds.
Leaf mold is one of the best soil amendments because it adds nutrients, trace minerals, good bacteria and fungi, and helps to support a diversity of organisms and earthworms.
Although leaf mold can be used as a mulch, it’s different from regular leaf mulch because it’s been allowed to decompose until the leaves are no longer recognizable. The resulting organic matter has a dark brown color and a fresh, earthy smell. Although dry leaves can be incorporated into compost as a good source of carbon (80:1 carbon/nitrogen ratio), Palmer and other regenerative gardeners recommend using fallen autumn leaves to make leaf mold as a separate soil amendment.
All deciduous tree and shrub leaves will make good leaf mold, although black walnut leaves contain a natural herbicide which may prevent flower and vegetable seeds from germinating. Using a variety of leaves is ideal because they will attract diverse insects and micro-organisms to the pile.
A pile of leaves left alone will eventually decompose and make leaf mold; however, gardeners can speed up the rate of decomposition by shredding the leaves first.
I’ve experimented with different shredding methods. First I tried running over the leaf pile with a lawnmower, but I had better success by putting the leaves in a trash can and shredding them with a weed-whacker. This year, I invested in a tool that is, as Liberty Hyde Bailey would say, “precisely adapted to the work to be accomplished.” It’s an electric leaf mulcher on legs that uses heavy-duty trimmer line for shredding. Dry leaves are dropped into a large bowl on top of the stand, and the shredded leaves drop into a bag underneath.
Once the leaves are shredded, I dump them into an empty raised garden bed, and then add a nitrogen source to jumpstart the decomposition process: alfalfa meal, blood meal, flaxseed meal or manure. The leaves are kept moist and turned every two weeks or so.
By spring, the leaf mold will be ready to work gently into the garden topsoil with a shovel. In addition to soil enhancement, I already mentioned that leaf mold can be used for mulching around garden plants. Eliot Coleman, author of “The New Organic Grower” (1989), particularly recommends using leaf mold for vegetables in the cabbage and carrot families as an overall “health tonic.”
Leaf mold isn’t a new idea. Although Liberty Hyde Bailey didn’t consider leaf mold a gardening tool as Nigel Palmer suggests, leaf mold is mentioned several times in “Garden-Making,” as a mulch and as a soil amendment. One thing is for sure: If the father of modern horticulture were around today, he would be horrified to see the huge piles of bagged leaves that end up at the local landfill every fall.
Rhonda Nowak is a Rogue Valley gardener, teacher and writer. Email her at Rnowak39@gmail.com. For more about gardening, check out her podcasts at https://mailtribune.com/podcasts/the-literary-gardener and her website at www.literarygardener.com.