Yes, pizza boxes can be composted if you follow the proper procedures before placing them in your compost bin or outdoor pile. Even if it has some grease or chunks of cheese on it, it’s okay. Just bury the box deeper into the pile to prevent pests.
How to Add Them to Your Composter
- Remove any plastic or wax paper from the interior of the box and any crumbs or loose topping left behind. A little grease or food is fine, but otherwise, you only want to compost cardboard material.
- Cut the box into as many small pieces as you can with a knife or scissors. If you have a powerful paper shredder, you can save time by shredding any non-food or grease sections. In my compost, cardboard shreds break down the quickest and provide a lot of beneficial aeration.
- Add the material to your composter like any other carbon source, making sure the ratio is balanced with the right amount of green materials. If you’re concerned about attracting pests, bury the pizza box scraps deep in the pile’s center.
- Turn or mix your compost every couple of days to help keep heat, air, and moisture levels at optimal levels. This helps break down your compost ingredients quickly.
- Expect any type of cardboard, even greasy ones, to decompose in two to three months. In less than a month, shreds of cardboard in my composters have become unrecognizable.
How Long Do They Take to Decompose?
Several factors influence how quickly a pizza box decomposes. Under optimal conditions, a cardboard box can biodegrade or decompose in about 90 days, if prepared properly.
Consider Putting Them in Green Bins
In the United States, Canada, Australia, and the United Kingdom, green bins are large containers that collect biodegradable waste, food waste, and compostable materials. The city collects the contents of these green bins and composts them to keep food waste out of landfills.
If you don’t have a composter, you can easily throw the boxes in the local green bin.
Pizza Boxes Are Not Recyclable
Contrary to popular belief, pizza boxes are not recyclable.
The issue is not with the cardboard box, but with the pizza inside of it. Oils and grease “soil” the cardboard. Why do oil and grease cause problems when recycling paper products? The answer is straightforward: The paper recycling process requires a lot of water.
Paper is first sorted and washed in a soapy solution to remove dirt, dyes, plastic films, and staples. It is then poured into a large bin and mixed with water to form a slurry. It is then spread out and cut before being released back into the world using large rollers.
Unfortunately, oil and water do not mix. The presence of oil in the slurry can cause it to separate and become lumpy, making the batch unusable.
My Personal Recommendation
If you only eat pizza occasionally, I recommend composting the boxes they come in. If you eat pizza regularly, you might want to just throw away the boxes. All things considered, they take a long time to decompose. Even if you only compost clean, cut-up boxes, they are likely to emit odors and attract rodents and slow down the decomposition process.
If you want to be environmentally friendly and recycle the nutrients from some of your everyday waste, consider using the following instead.
Eggshells are a great source of calcium. Because they can take a long time to decompose, make sure to crush or grind them into small pieces before adding them. Don’t worry if a few small bits of shell are left over in the finished product.
Banana peels are high in potassium and are thus classified as green material. They will, however, attract fruit flies, so make sure to bury them deep within your pile.
The vast majority of vegetable scraps can be composted. Keep them in a bin in your kitchen, and when it’s full, add them to your pile.
If you want to speed up the decomposition process, blend the vegetable scraps—together with eggshells and banana peels—into a “waste smoothie” before adding it to your pile.