This Instructable is for a zero cost 3-bin compost made from pallets. It's zero cost because we paid nothing for it. We used screws leftover from building our chicken coop and pallets we got for free.

This compost bin is customizable. You can do a 2-bin system, 1 bin system, or double the bins.

The wife and I have been talking about composting for years but have never really committed. Now that we have a house and land, chickens and ducks, composting is a big part of our waste management plan for our animals and it'll make for great soil in our vegetable gardens when we get those going.

Supplies

Pallets- for a 3 bin compost we used 7 for the sides and middle and 2 for the top.

Drill, bits, pilot holes

Exterior screws 2-3" should be enough

Step 1: Getting Pallets

Do NOT pay for pallets. Businesses literally give these away. You can find ads for them on CraigsList and FaceBook Marketplace. We got all the pallets we needed for this project (and then some) from Tiles & More. They had about 50 stacked by their dumpster and put up a FaceBook ad begging people to come take them. Sometimes you can even find ads offering to pay people for taking pallets.

You want to look for pallets that have been heat treated but do NOT have an "MB" stamp on them. "MB" is Methyl Bromide a dangerous chemical that you do not want leeching out into your compost.

The info stamped on a pallet tells you were the pallet came from along with a country code, if it's heat treated (HT) or not, other treatments it may have.

If you look at the collage, all of these pallets have been heat treated and at least two of them came from Canada and one from the US. The second picture shows a pallet we found with the MB stamp. It was a nice pallet, but not usable for our purposes.

Step 2: Prep Work

Before we started, I setup the pallets how I wanted them and counted out how many I'd need. Originally we figured 7 pallets for the sides and middle sections, and then 1 more for the roof.

We moved all the pallets and supplies over to a far corner of our property that abuts MassPike and is close enough, but not too close to our yard and chicken coop. It's out of the way enough so that it isn't visible to people, but not too much of a hike to bring compostable materials back and forth.

Step 3: Attaching Pallets

For each side I used 3-4 screws, attaching evenly along the sides. I kept doing this until I had 3 bins set up.

Step 4: Add-on's

After getting the bins set up, we decided what making the compost bins deeper wouldn't be a bad idea. So we added additional pallets to the external walls. The wall between the first two bins we left alone, figuring it would be easier to transfer compost.

We added two partial pallets to the third bin to act as a roof. We drilled one in, the second we may add hinges to later.

"Doors" or chicken wire can be added to the front of the bins if you're concerned about pests etc. At the moment it's not an issue for us, but we'll make changes if it becomes one.

Step 5: How It Works

We're going to be following the Rodale Composting method, which is layering compostable materials like lasagna. Browns (leaves, paper products, yard waste, etc) and greens (coffee grounds, non-meat food waste, manures, etc) are layered on top of each other with the browns ALWAYS covering food waste (to reduce odor etc.)

The compostable materials break down as time goes on. You continue to add to the pile, water as needed, and turn the materials weekly. The first two bins we have will be for moving the compost back and forth (turning it) and then the third bin will be for the finished compost.