I am considering using cardboard to mulch my new garden bed. Sheet mulching, as it is usually called, is a no-dig gardening technique, meaning it is a way to make a garden bed right on top of weeds without having to till everything up. By putting layers of cardboard over the ground, you create a barrier that very few plants can push their way up through, so it means fewer weeds to deal with.
And that’s just the beginning of the benefits. Cardboard/sheet mulching:
- * Helps build your soil because the organic material breaks down.
* Takes less work. You don’t have to dig, there are fewer weed.
* Allows you to shape your garden any way you want.
* Attracts worms to the garden. (But also snails.)
* Uses recycled materials–cardboard boxes or newspaper that most of us have lying around anyway.
Like with any gardening technique, there isn’t one clear way to do cardboard mulching, but there is a general principle involved. Here is the rundown, as I understand it:
1. Select your garden site.
2. Make a weed-free barrier around the garden. Use wood or stone or something like that to lock in the shape of the garden.
3. Stamp or mow down the weeds. Pull any weeds with deep roots, like dandelions.
4. Water the ground.
5. Lay down the cardboard. Remove tape and other things that won’t decompose and lay the cardboard in the shape you want. Overlap so there are no holes. Here’s an example of what it looks like:
(Image courtesy Native Sanctuary)
You can also use newspaper, but it apparently takes longer to decompose and doesn’t work as well.
6. Thoroughly water the cardboard. Soaking the cardboard speeds up its deterioration. Native Sanctuary suggests that you turn the water on and leave it for a few minutes.
7. Put compost on top of the cardboard.
8. Put mulch on top of the compost. Some websites recommend a layer of organic material like grass clippings under the mulch, but just as many seem to skip that and just use wood chips or hay.
9. Plant. At the point, you can put the plant right into the garden, although you may have to cut down into the cardboard to get at the ground.
That seems to be the common order. However, this site recommends that you put the compost under the cardboard, which I could see working too. Here’s their order:
The idea behind sheet mulching is to layer the ground in a way that is similar to how a forest floor works.
So, if we are looking at the above image of layers of a forest floor, I guess the original soil would be your bedrock (c), the cardboard would be the subsoil (b), the compost would be your surface soil (a), and the mulch/grass clippings would be your organic matters (o)?
Or would the cardboard be the bedrock and the plants the organic matter? Hmmm…
Anyway, here is a video of two people planting a sheet-mulched garden, which explains the technique a lot more simply than I just did:
If you have sheet mulched, I’d love to hear how it went for you. Did it get rid of weeds for good?