Decomposing Boxing Day

December 26, 2007

Sheet-mulchI’m celebrating Boxing Day in a new way this year – I’m putting all the cardboard boxes saved up from Shipping Month, aka December, to use in my Permaculture garden, by making sheet mulch.

Google sheet mulch and Permaculture. (For those not in the know, Permaculture is a fairly recent term for cultivating an edible landscape that establishes positively reinforcing relationships between water, soil, insects, microbes, sun, etc…for the purpose of sustainably and organically feeding its designing human.)

Sheet mulches are an easy way to ‘compost in place’, delivering all the water-borne yummies to the plants instead of under the compost pile. Design-wise, sheet mulching also avoids the not-so-Neighborhood-Association-Friendly look of compost piles, so it’s a tricky way to subvert the negative effects of suburban sprawl – grow a food landscape!

How the cardboard boxes fit in: They’re the weed suppressant. I am making mine according to the directions in the book Gaia’s Garden: A Guide to Home-Scale Permaculture, by Toby Hemenway. I’ve done a couple sheet mulch beds already, and the blueberry and quince bushes seem very grateful. You’ll need to make a collection of boxes, as well as manure/finished compost, and a high-nitrogen additive like bloodmeal, or cottonseedmeal.

First, I slash the existing vegetation to the ground. Then I soak the ground (from my rain barrel of course). Then a thin layer of manure or meal to attract the earthworms from wherever they come. Then the cardboard. (Hemenway says you can use 1/4″ of newspaper, and some say the results are better with paper – but I read my local online, so I just have cardboard.) Overlap the pieces 6″ so the weeds won’t wiggle through. Now soak the cardboard so it won’t blow away. Sprinkle another layer of high-nitrogen meal, then cover with 8-12″ of bulk mulch. I use the leaves that just fell from my hickory trees, and try to fish out as many nuts as I can for eating. I dampen the leaves to keep them stable and start the decomposition process, and add a bit more meal as I build this thick layer. Then the compost goes on, and finally, a ‘pretty’ mulch, like pinestraw or bark chips, for Neighbor Approval.

The final advantage to sheet mulching is that then the whole landscape is an opportunity to compost kitchen scraps – if you don’t have a Bokashi bucket or a wormery. Just lift up the corner of a mulch and tuck under those apple cores. I have not seen animals digging my mulch yet – well, except for the earthworms, who are very welcome.

(Photo by the author, under her plum tree.)