The dark side of lasagna gardening

Sheet mulching in relation to recycling

by Mario D. Vaden .. also see Barkdust Benefits, Calculating, Ordering

 

The meaning of dark side does not mean bad. It means little light has been shed on a certain aspect of the subject. A vast assortment of organic gardening pages already exist about using paper products for mulching in gardens, and that's where plenty of light was shed on other aspects. But none I read prior to writing this discussed what happens when paper and cardboard are removed from the recycling process in urban areas.

Lasagna Gardening is the practice of mulching with layers, sometimes by laying newspaper or cardboard over soil or vegetation, then covered with compost, straw, bark, leaves or other mulch.

Laying compost without paper can also be called lasagna gardening.

This page introduces sheet mulching from a broader perspective including effects on resources and environment as an if-the-shoe-fits topic where recycling is available.

Lasagna gardening can be called sheet composting, used for no-dig gardening and some organic gardeners. The practice is often promoted to smother weeds, improve soil conditions and sometimes avoid mechanical cultivation like rototilling or double digging.

Lasagna gardening generally does not need herbicides when the first layers are spread and some gardeners have that in mind. But how can that practice affect the environment or resources locally and more distant?

Consider a few extra factors

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 new pulp from trees. If gardeners stockpile or hoard cardboard for sheet mulching, those resources cannot be recycled to use as packaging again. In this way, gardeners may sacrifice a few environmental benefits. The resource they won't recycle simply decays. Removing paper or cardboard from the stream of recycling uses more energy reserves. Sheet mulching increases energy use; increases sulfur dioxide emissions; requires more trees cut and processed; increases labor expense. Basically, it 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 million 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 energy. Recycled paper produces 73% less air pollution. All things considered, Lasagna no-till gardening using paper can cause more pollution.

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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

An alternative to paper is just using different kinds of leaves from the property, flattened beneath a layer of compost or mulch. I have used just mulch countless times for myself and some customers, and that works too. When un-shredded leaves are layered flat beneath mulch is seems to smother weeds even better. But even when mulch or bark is used all by itself, I find 95% of grass and weeds are eradicated.

The broader look at sheet mulching should not be controversial based on the facts and easy options. In areas where curbside or local recycing is not available, sheet mulching may be a desireable alternative allowing cardboard or paper to decay and return to the earth rather than filling a landfill.

You could be surprised at the number of oddball emails I receive from people who misinterpret this page. One guy called and said their little garden club had an argument stemming from this page, to the point the group splintered apart !!

The purpose of this page is not to reinvent the wheel. It was put online to cover an aspect rarely covered by the other resources.

In closing, I can vouch that mulching along with chips and leaves is a great way to improve soil. Keep in mind though that it rarely breaks soil compaction properly in areas where dogs and children played on moist or irrigated soil areas, and places where construction compressed surface particles. Rototilling, digging or double digging may be the best alternative before laying layers of mulch and compost. Also learn where your mulch and chips are coming from to make sure it wasn't something like a birch removal where the trunks were injected systemically for aphic control (etc., etc.)