Sheet Mulch to Smother Weeds and Build Soil

Courtesy of Tilth Alliance

When I first moved into my house, sheet mulching quickly became my new best friend in the quest to turn my front garden bed – a sea of weeds – back into something resembling a garden.

Sheet mulching is a relatively easy and cheap/free way to reclaim your garden or create a new garden bed using just 3 ingredients: water, cardboard or newspaper, and lots and lots of mulch.

The thick layers of mulch and compostable weed barrier suffocates and kills unwanted grass and weeds. The resulting dead plant material then decomposes and enriches the soil. It also brings in billions of decomposers – beneficial bacteria, worms and insects – and helps soil retain moisture during the summer.

Easy as 1, 2, 3…4

1. Gather your materials

Lucky for me (but not our wallets), my husband and I had recently been on an Ikea shopping spree, furnishing our new home. We had tons of large pieces of cardboard – perfect for sheet mulching! (Any cardboard or newspaper will work. Just be sure to remove any tape and it’s preferable to use sheets that aren’t heavily dyed.)

We also scored a huge pile of wood chip mulch via the “free” section on Craigslist.org. (ChipDrop.in is also a great source of free wood chips, direct from arborists).

With these materials ready to go, we could start sheet mulching!

2. Spread out your cardboard or newspaper

We covered our garden bed in flattened cardboard, making sure the layers overlapped and that the ground didn’t show through. This layer eliminates weeds and grass by blocking sunlight and forcing decomposition.

We arranged the cardboard around existing shrubs, leaving space around their stems.

When we were done laying out the cardboard, we soaked it with a hose. In retrospect, using a sprinkler probably would have been easier (and my shoes would have stayed a lot drier).

3. Spread your mulch

We spread a super thick layer of mulch over the cardboard.

Doing a little math ahead of time to figure out how much we would need for good coverage would have been helpful. We were a little too enthusiastic to jump in and didn’t take this step. A layer that is 12 inches or deeper is ideal, but we ended up with a thin mulch layer on one end of the garden bed – and this was definitely where weeds tried to first re-establish themselves.

4. Water and wait

We finished up the project by watering the area again and walked away to let nature do the rest.

You can spot plant your new bed by moving mulch aside, cutting through the cardboard, digging a hole, amending the soil and putting in your plant.

Sheet mulching didn’t kill all our weeds, but it definitely gave us a healthier garden and a head start on maintenance, making it easier to pull any weeds that burst through the layers.