The dark side of lasagna gardening, sheet mulching
Occassionally, opposite of sustainable & green living
Copyright 2009 - Mario D. Vaden
The meaning of "dark side" here does not mean "bad". It's referring to a shortage of ight shed on this angle of the subject. A vast assortment of organic gardening web pages can be found about what happens in gardens when paper products are used for sheet mulching. That's where plenty of light has been shed on this subject. How about if we shed some light on that dark shaded side.
Lasagna Gardening is the practice of mulching with layers, often by laying newspaper, cardboard or paper over soil or vegetation, covered over with compost, straw, bark or other mulch. This page introduces sheet mulching from a broader perspective, including resources and environment. Its an if-the-shoe-fit's topic for gardeners in areas where recycling is available with comparable benefits.
Lasagna gardening can be called sheet gardening or sheet composting, and is commonly used for no-dig gardening, some organic gardeners, and some lazy gardeners. Each with reasons or excuses. The responsible gardeners will have reasons and usually understand soil and water.
The practice is often promoted as an "easy way" to garden: sometimes skipping weeding, cultivation, double digging and other work that involves other work and effort.
Lasagna no-till gardening does not need herbicides when the first layers are spread and some gardeners may have that in mind. And another promo for lasagna gardening is not mixing soil horizons for concern or fear that cultivatig may promote compaction. But if the area is lawn, sheet mulching can cover potential drainage issues related to surface compaction. If its just a thin film of compacted soil, no big deal, but deeper compaction may need actual work, not just top layers. Cultivation can't erase all the 1000s of microorganisms per spoonful of soil, so don't omit that alternative. Every angle of soil care is essential, and we don't want to hide problems merely for the sake of ease. Sometimes double-digging is worth the effort too, followed after with a generous layer of mulch. Now the extra facts:
Consider the facts ...
If gardeners hoard cardboard for sheet mulching, those resources cannot be recycled to promote green living or reduce the carbon footprint. In this way, practitioners of no-dig gardening sacrifice an environmental benefit. And the resource they won't recycle, simply decays. Recycled cardboard needs just 75% of the energy used to make new cardboard, and decreases the emission of sulfur dioxide - Wikipedia Sulfur Dioxide - produced when making pulp from trees. This indicates that:
Sheet mulching increases energy us; increases sulfur dioxide emissions; requires more trees to be cut and processed; increases labor and wage expense elsewhere; and sheet mulching wastes water, oil and energy
Sources, with some variation, state the same basic information. Recycling 1 ton of cardboard saves 46 gallons of oil and 6.6 milion Btu's of energy. Recycling 1 ton of paper spares 17 trees, 7,000 gallons of water, 79 gallons of oil, 587 pounds of air pollution and 4,077 Kilowatt hours of energy. Recycled paper produces 73% less air pollution. All things considered, Lasagna no-till gardening can have a larger carbon footprint and cause more pollution. If working with the earth and exerting more exercise is a better alternative, sheet-mulching becomes wasteful.
The activity of worms in no-till sheet mulching adds enthusiasm for many gardeners, but they also need to realize that the worms did not just materialize like Captain Kirk. Before the sheet mulching was applied, worms were there. And keep in mind that benefits of no-till gardening are readily available without use of paper or cardboard. Recycling does not mean that someone cannot garden organically.
One alternative worth exploring as an alternative to paper, would be using different kinds of leaves from the property, flattened beneath a layer of compost or mulch.
If you search for facts about recycling cardboard, many references will be found with this information. There are literally scores of municipal and other websites with the information. Here is a generic reference on just paper recycling from Wikipedia:
Recycling Paper Article - Wikipedia
The broad look at sheet mulching will be controversial. Gardeners who want to improve, simply glean more information, weigh the options and choose a plan. In areas where recycing is not available, sheet mulching may indeed be the right alternative, allowing cardboard or paper to decay and return to the earth. Rather than filling a landfill.