When my former workplace sent me to WFH during the early days of 2020 and COVID I decided to rip half my backyard out and turn it to garden. The year before I’d had a successful run of growing tomatoes and peppers. I needed more space for more veggies. I used a no dig gardening method I found on youtube (I can’t find the channel right now, he’s an older British guy who used to have a TV show.) That channel led me to no dig gardening and the use of cardboard as a weed barrier plus the use of wood chips in and around the garden.
Essentially for the cardboard, you lay down a sheet of cardboard that has had all the tape and labels removed, wet it down and then either plant through it or put a top layer of compost or wood chips over it. The cardboard keeps moisture in while also breaking down. The cardboard works really well at suppressing most weeds and eventually breaks down to add to your soil. My experience with cardboard has been fantastic.
The hardest part is getting enough cardboard of a large enough size. I raided the local Charbucks and other recycling bins for enough cardboard to use. My own cardboard intake was too low to work, and when I did have cardboard it was generally pretty small in size which is frankly a nightmare to set up. It requires more work to remove all the tape and labels and there is the need to overlap the flaps so there aren’t breaks in the coverage. I found that for my use a single layer of cardboard worked for under compost. It killed off the grass while I was still able to plant through it. For under wood chips and in areas I planned as walkways I used a double layer.
Let’s talk about shreds of cardboard. Shredded cardboard is a little harder to work with. To keep it from blowing away you need to soak it, and even after a soak, if it it not well meshed together it can still blow away creating a mess that will piss off neighbors. All that said, I like shredded cardboard. It creates a really superior weed barrier due to the thickness that the wet shreds can be applied- rough 3 or 4 layers of cardboard thick. That combined with a layer of wood chips means no weeds come up through the chips. It works really really well. I apply it much more thinly when I put compost over the top. It’s easier to dig and plant through than cardboard. Even wet cardboard has quite a bit of strength, particularly if you source heavier cardboard from larger boxes. Even wet they can take some work to cut through. While my hori hori knife cuts through it easily my trowel didn’t quite as easily.
Shreds can be easily moved to the side to get a plant in place, and even when damp or slightly dried it’s easier to cut through and plant.
If I have a need for large areas to be covered and weed blocked larger sheets of cardboard are better. Simply for speed of laying out the base. Big cardboard is still rough to process. It’s got staples, tape, and labels that need to be removed. I prefer the shredded stuff for smaller areas or areas that need patching. I have a garden that runs along the side of my house and the shreds are perfect for this area. It can be sculpted to exactly where I need it and when damp it stays put.
So a note on recycling bins from businesses. Some businesses lock their cardboard dumpsters down or won’t give you access to it. At Charbucks the kids leave the dumpster open and when I asked, they didn’t care if I snagged cardboard out of it. CVS is similar. Other locations have a large sized locked dumpster and you have to go into the store and ask, they will give you what they have on hand but won’t have much else. This is the case at the local grocery stores. Many of these locations get paid for their crushed and baled cardboard. It’s always a best practice to ask, but also I’ve gone back to that Charbucks over the years and they don’t care if I snag cardboard from their dumpster. There is another place closer to my house and they don’t allow dumpster diving for cardboard.