Sheet Mulching is a very basic and important Permaculture skill.
Sometimes called “blanket composting”, “no-work” or “no-dig” gardening, it is very representative of Permaculture in terms of modeling Nature.
This is the start of the Medicine Wheel Garden. As you see, we are layering the Sheet Mulching right on top of the lawn. No need to dig or pull weeds. They become part of the nutrient base for the new garden. See full guidelines below.
The Medicine Wheel in full bloom.
It is a great way to build healthy soil fast, and is an effective means of carbon sequestration.
Sheet mulching is estimated to sequester 2.2 pounds of carbon per square foot – in a big garden, say, 0.4 acres, that’s 17,424 square feet. — that makes over 38,000 pounds of carbon removed from the atmosphere — 19 tons!
This estimate is by Donella H. Meadows (1941-2001) who was an adjunct professor of environmental studies at Dartmouth College and director of the Sustainability Institute in Hartland, Vt.
GUIDLINES FOR SHEET MULCHING
SHEET MULCHING is a fast, labor saving technique for building beds and suppressing weeds. For immediate planting, use perennials, large seeds, or make soil pockets for annual starts or small seeds. It is ideal to prepare new beds by Fall for Spring planting!
QUICK METHOD: Choose the area where you want to establish your new bed. If the ground is compacted, use a garden fork to aerate it a bit. Not turning it, but send the tines of the fork down vertically, and lift or rotate a bit without disturbing the soil or exposing soil to the air. Keep in mind that the sheet mulching will help aerate the soil. If you get the layers right, it will attract worms that will do the tilling and aeration for you!
Put down some manure, 1-2″ thick.
Cover with cardboard or 3-4 layers of newspaper. (Do not use shiny color pages, or colored cardboard. )
Soak each layer. Place another light layer of manure on top of the cardboard. The cardboard will rot, but first it will kill the plants under it, providing nutrients to the bed, as well as aeration through the root system.
Next, add 6″ straw, leaves or sawdust. (Manure from Camelids, such as llamas or sheep is already fully digested and ready to use.) Add a light soil layer.
Repeat these three layers: manure 2″, leaves/straw 6″, soil 1/2-1″ until the sheet mulch layers are ideally 18″ deep.
Add in any kitchen waste you have to the early layers. This will help attract worms.
Worms. You may inoculate your sheet-mulch beds with worms, but if you do the layers right, the worms will come.
If you are setting up your sheet-mulch bed in the Fall to winter-over, this is best.
Finish with 8-12″ layer of leaves, and cover with pine-needles if you have them. The pine needles will balance our Boulder valley alkaline clay soil. The needles interlock and will not blow away. Or, carpet will do. The carpet will stabilize the beds and help keep moisture in, for the right environment for worms.
For immediate planting, make soil pockets to plant transplants or large seeds. If you want to plant small seeds, put down a 2″ layer of compost/soil mix as your top layer.
ANOTHER APPROACH (from Permaculture Activist)
Wet area to be mulched the day before you plan to mulch.
You will want to soak each layer as you put it down – moisture speeds up the decomposition process.
Slash existing vegetation. Don’t pull up the weeds – it would disturb the soil and is not necessary.
Add soil amendments depending on soil type. Gypsum or lime and rock dust.
Put down a layer of high nitrogen material: chicken manure, fresh greens, whatever is on hand that is high in nitrogen.
Poke with pitchfork and rock back and forth to aerate heavy clay.
Spread several layers of newspaper or one layer of cardboard.
Spread a thin layer of food waste, decayed leaves or garden scraps.
Put down 6″ of straw, leaves or grass.
Add 4″ to 6″ of finished compost, seaweed or well rotted (3-month old) manure.
Finish with a layer of high carbon material: pine needles, straw, seagrass, leaves, wood chips, bark, sawdust or rice hulls.
First, plant any large trees or shrubs.
Sprinkle soil with dolomite (and gypsum for clay soil). Sprinkle chicken manure, blood and bone (for nitrogen). Optional – spread compost scraps for the worms.
Add weedy or seedy material. Do not dig, level or weed.
Sheet mulch with newspaper or cardboard – cover completely.
Apply 7.5cm of horse or poultry manure in sawdust or straw, leaf mold or seaweed.
Follow with 15cm dry, weed/seed free material: pine needles, rice husks, leaf mold, straw, bark, chips, sawdust or any combination.