What to do with the stack of flattened cardboard cereal and Amazon boxes cluttering my cabin?
I realize that most folks don’t give them a second thought, just toss them into the trash or chase down their embers floating out from the fire pit. But why landfill or burn something that could be put to other good use?
Best idea is to use them as sheet mulch, which is simply composting on top of the ground. Whether you use it to smother weeds between shrubs or pepper plants, or need to extend or start a new garden bed, this is a good way to smother weeds and improve soil. Sometimes I just tear them into hand-size pieces and toss them onto my composting leaf pile and throw some old compost on top, and they simply disappear into the mix.
But now I read on various online gardening sites that I shouldn’t even use them in the landscape, which turns out to be just another erroneous myth that needs busting.
I call widely shared but easily debunked recommendations “mythinformation.” Most of the weirdest beliefs and practices passed down through generations or making lightning-fast rounds on the internet are based on conflated, blown out of context, cherry picked tidbits found buried in extreme research. But they sound so good they spread like wildfire and become standard garden lore - often repeated by sensation-seeking journalists and occasionally even in Extension Service articles.
Example: Eggshells do not add calcium to the soil. Yeah, they do, but only after their original rock-hard calcium carbonate is broken down and converted into calcium citrate which is easily absorbed by roots. This is done slowly but naturally in highly acidic soils, but in most gardens the eggshells remain intact, unavailable to plants, for years.
However, if you crush them to bits and fizz them with a little vinegar (natural acid), it happens very quickly. This is basic chemistry, not folklore.
This doesn’t mean don’t recycle eggshells; I crush and toss them into the compost anyway. I just don’t sprinkle them around my tomatoes because it doesn’t work like that. Oh, and another myth: snails and slubs crawl right over them, no problem.
I can go on and on about garden myths, but the latest making the social media rounds is the idea that using cardboard as mulch in a garden is bad, based entirely on one blogger who seriously misinterpreted data that had nothing to do with mulching. The blogger claimed, a bit too emphatically, that cardboard contains toxins and should not be used. Period.
It was that emphasis that got me riled, and started me digging deep for the real deal. I won’t “gish gallop” you with details, hoping you trust this skeptical old scientist to have done thorough and diligent research on replicable studies. But the bottom line is that layers of regular cardboard, like used for packing and shipping, is made with plant-based glue, and has fewer toxins than plain old natural wood chip mulch.
Granted, cardboard mulch looks funny, which is why I cover mine with a little bark mulch or a thick layer of tree leaves which I find by the bagsful set out nearly on neighbors’ curbs. Within weeks you could pull a little of it back to peek underneath, where you will find the once-hard soil dark and crumbly and teeming with zaftig earthworms churning it all down deep, creating tunnels for water, air, and roots to penetrate deeply.
And it’s a good way to recycle my stack of cardboard boxes. Regardless of what bored bloggers share without digging deep for real facts.
Felder Rushing is a Mississippi author, columnist, and host of the “Gestalt Gardener” on MPB Think Radio. Email gardening questions to rushingfelder@yahoo.com.
