As recently as 50 years ago, nobody mulched their vegetable gardens. Hoeing and hand weeding kept rows clean, and who cared how much water you used? There was plenty! Mulching has revolutionised how we manage weeds, water and build organic matter in our gardens, but modern mulching methods did not evolve overnight. Here is a review of three big mulching trends of recent decades, and what they mean to how we garden today, and perhaps tomorrow.
Ruth Stout’s No-Work Gardening (1979)
After Connecticut gardener Ruth Stout discovered that covering her garden continuously with a deep hay mulch improved the soil, retained moisture, and prevented weeds, she wrote a phenomenally successful book on no-work gardening.
“You need at least twice as much mulch as you would think,” she wrote in a Mother Earth News article that discusses her mulching methods in detail. I had learned as much by visiting Stout-style gardens, where there was another glitch: too much wildlife. Deep, year-round mulch proved irresistible to snakes, chipmunks, and voles, so embracing Stout’s method full on required acceptance of critters that find easy cover in mulch.
Yet Stout’s influence on modern organic gardening cannot be underestimated. Most of us mulch soon after the soil warms in late spring, and then again in autumn to protect soil in winter. Many of us grow potatoes in mulch. All are lasting legacies from Ruth Stout.
Lasagne Gardening (1998)
Named and refined by Pat Lanza, lasagne beds are created by layering different types of organic matter into a big mound, and then letting them rot together into a cushy planting bed. By the book, a proper lasagne bed consists of at least six layers of compost, peat moss, newspapers, shredded leaves, etc., which can become quite a project. Then it takes a year or two for the layers to meld into fertile soil.
Making lasagne beds is not as hot as it once was, but when you use compost and cardboard to lay the foundation for a new bed, you are using Pat Lanza’s mulching methods. Time has taught us that only a few layers are needed where earthworms are abundant. Simply covering the soil with rich organic matter (such as grass clippings or manure), then clean cardboard topped by enough organic much to keep it moist, attracts so many earthworms that they become active tillers of the soil in the new bed.
The Wood Chip Revolution
Starting in the 1990’s, bigger and better wood chipping machinery became available to the timber industry. Culled trees could be chipped “in-woods,” which made it practical and profitable to package and sell a new product: wood chip mulch.
The even textures and durability of wood chip mulches quickly won them places beneath ornamental shrubs, and their cushioning effects led to their widespread use in playgrounds. As mobile tree-trimming crews began using on-site chippers, piles of ramial wood chips (consisting of fresh green branches and some leaves) became free for the asking from local arborists.
It wasn’t until the Back To Eden film came along in 2011 that a case was made to use wood chips as a foundation for a prosperous food garden. Continuously replenishing a deep wood chip mulch keeps the soil cool and moist, with plantings made in compost-enriched openings in the mulch. Over time, fungi that colonizsethe rotting wood chips contribute to soil fertility.
Perpetual mulching with wood chips is a perfect match for urban “food forests,” in which food-bearing trees, shrubs, and annual crops are grown in community, with frequent footsteps from their human keepers. And while most Back To Eden gardeners do use wood chips for pathways, rotted leaves (leafmould) is a treasured mulch for hard-working beds. Leaves or hay also make a good alternative when free wood chips fail to materialise.
Organic gardeners never much embraced mulching methods based on plastic, but large-scale agriculture did. One of today’s pressing concerns is reducing agricultural use of plastic mulches, which control weeds and conserve water, but are not sustainable because plastic stays plastic. In many instances, biodegradable mulches comprised of compost, cardboard, grass clippings, leaves, hay or wood chips can replace plastic mulch and sequester a bit of carbon at the same time. Nature loves to mulch. We need to keep learning better ways to mimic her ways.