Composting Egg Cartons – What you NEED to know | Growit Buildit (2024)

Eggs are one of the most consumed foods in North America, and that also means that we generate a lot of egg cartons. While recycling items is always preferable to throwing things away, the best forms of recycling is when we find new uses for our old items.

You can compost egg cartons that are made from paperboard or cardboard, as these materials are made from wood pulp or recycled paper and are biodegradable. The carton can be torn into small pieces and placed directly into a compost heap or compost pile, where it will count as part of your ‘brown’ material for your C:N ratio.

I used egg cartons made from recycled paper in my compost piles for years as a brown material. And during that time I only used the bottom half of the egg carton, as it was always ink free. I did this because I wanted to avoid any colored inks, as they almost always contain trace amounts of heavy metals.

Recently however (December 2023), I reached out to several egg carton manufacturers to inquire about the source of their recycled material. Three different egg carton manufacturers stated that their source material was recycled newspaper which often has colored inks on it. And if you want to be completely organic, you cannot include anything with colored ink[1]. Because of this information, I no longer compost egg cartons at all, nor any paper board products such as the drink holders they give you at fast food restaurants, etc.

In this article I will go through the different types of egg cartons that you may encounter and which ones can be composted, as well as other good practical uses for egg cartons.

Types of Egg Cartons

In general you may encounter 3 types of egg cartons at the grocery store.

• Paperboard Egg Cartons
• Plastic Egg Cartons
• Styrofoam or polystyrene egg cartons

Egg carton recycling / composting reference table

Paperboard / Cardboard Egg Cartons

Egg cartons that are manufactured from wood pulp or recycled paper are known as paperboard egg cartons. They have been in use since the 1980’s, when the environmentalist movement gained steam. To make them, recycled paper or cardboard is blended with water and made into a slurry. This is then pressed onto a mold, and voila – the egg carton is made[2].

Should you compost paperboard egg cartons with ink?

While some sources will state that inks are generally soy based and safe to compost, studies have repeatedly found that colored inks will often contain trace elements of heavy metals, even in food packaging[3]. If you would like to read more on this topic, I suggest you read this section of our guide to risks of composting paper/cardboard.

Now, the amount of heavy metal from the ink on a single egg carton would be quite small. Even if you composted with egg cartons (ink & all) for years it would probably take a very long time for the amount of heavy metals to build up to dangerous levels in your garden. None the less, if you can reasonably avoid this risk, you should do so as a ‘best practice’.

In my own compost piles, I only compost the bottom half of the egg cartons to avoid any addition of heavy metals from the ink being transferred to my compost, and then to my garden soil. I do this because it is a reasonable amount (low) of effort to eliminate a risk.

Plastic egg cartons

The plastic egg cartons you can encounter at the store are made by a lightweight clear plastic known as PET (Polyethylene Terephthalate). The plastic is heated and pressed into molds to form the carton.

Plastic egg cartons are recyclable, which will reduce landfill waste. Recycled plastic uses less energy to be reused as opposed to making new.[4] But they are not biodegradable, so should not be composted.

Styrofoam / foam egg cartons

Foam egg cartons have been around since the 1950’s. They are manufactured by taking small beads of polystyrene and heating them, and then pressing them into a mold. Egg cartons made from Styrofoam are not biodegradable nor compostable.

Depending on your location or waste company that services your neighborhood, you may be able to recycle Styrofoam. You will need to check with the waste company, as recycling polystyrene is more complex and expensive than other common materials. [5]

Due to the fact that foam egg cartons are not biodegradable coupled with the difficulties recycling them, it is better to purchase egg cartons made from more earth-friendly materials, such as paperboard.

How to compost egg cartons

To compost egg cartons, simply tear up or cut up paperboard egg cartons into small pieces and add them directly to your compost pile or compost heap. It will count as brown, carbon rich material.

The smaller the pieces of egg carton, the better it will mix in your pile, and thus breakdown faster. This is important as the paperboard egg cartons are high in lignin which is slower to decompose than other brown materials.

Can you compost egg cartons with egg spilled on them?

Sometimes bits of egg accidentally spill, or an egg gets stuck to the carton. You can compost egg cartons that have small amounts of egg residue on them. While standard composting practice says not to compost proteins, I have found over the years that it is ok if you have a hot pile, or the amount is quite small. Problems may arise if your pile isn’t hot or there is a lot of egg, as your pile may now attract animals or hatch flies.

However, if there is egg residue or egg on a carton, it can no longer be recycled and should be thrown out in the trash.

Final thoughts

Egg cartons made from paperboard are an excellent source of brown material for a compost pile. If eggs are a standard part of your household’s diet, then you can slowly accumulate them overtime, so you always have a supply on-hand. It is easy to process and stockpile, making it available to most anyone.

Click here to see 101 household items you can compost