How to Sheet Mulch

You can build new garden beds full of rich, fertile soil without ever putting a hand on a shovel! Sheet mulching, also known as sheet composting, layers cardboard, compost, and vegetative matter right on top of lawns or weedy areas. Over the course of a few months the mulch and the underlying sod and weeds decompose. Sheet mulching increases the population of beneficial soil microbes and worms, improves soil's capacity to retain nutrients and water, and reduces weeds. But the best thing about sheet mulch is it creates fantastic new garden spaces with only a small amount of effort on your part!

Cardboard

Compost

Leaves

Grass clippings

Wood chips

Bow rake

Galvanized metal edging

Determine where you want to site your new garden bed. Experiment with different garden bed sizes and shapes by using a garden hose to help visualize the border of the bed.

Prevent grass from creeping into your new bed by installing 6-inch wide galvanized metal edging around the entire perimeter (hint: use the hose to delineate the bed and help guide the placement of the edging). Pound the edging into place with a heavy rubber mallet and secure it with metal landscaping pins every 24 inches. Overlap each strip of edging 6 inches and leave 1/2- to 1-inch of edging above the soil line.

Mow down any weeds or grass within the perimeter of the bed. Kick start the microbial activity in your soil by spreading 1/4- to 1/2-inch of compost over the soil. Then water the bed, soaking the soil down to at least 5 inches.

Now place a single layer of heavy-duty cardboard over the entire bed. Use a box cutter to cut the cardboard to fit if your bed curves. This mulch layer smothers underlying grass and weeds and prevents weed seeds from germinating by blocking out light. Be sure to completely cover the bed by overlapping each piece of cardboard 6 to 8 inches. Saturate the cardboard with water to aid its decomposition.

Add a 2-inch layer of finished compost or composted manure on top of the cardboard. Avoid using horse manure because it typically contains tons of weed seeds.

Place a 4-inch layer of mixed vegetative matter, such as grass clippings combined with shredded leaves or straw, on top of the compost.

Top the bed off with a 2-inch layer of wood chips.

Wait 6 to 8 months for the mulch to break down and then plant directly into the rich soil in your new garden bed.

It is okay to sheet mulch around existing trees and shrubs, just be sure to leave 6 inches of space between the plant and the mulch layers.

Remove any packing tape or staples from the cardboard before using it.

Great sources of free cardboard are appliance, liquor, and grocery stores.

Don't skip the edging step! It is essential for preventing grass from infesting your new bed.

Avoid using shiny, colored cardboard as it may contain heavy metals or other toxins