Are egg cartons biodegradable? Can they be composted?

  • Date: May 14, 2022

Eggs are a staple in the diet of many people. Nutrient-rich and easy to prepare they are a great option for a quick, nutritious snack. With the average American eating not-far-off 300 eggs a year, that means a LOT of egg cartons (and eggshells) could potentially end up in landfill. This raises the question – are egg cartons biodegradable and can they be composted? Well, that largely depends on what the egg carton is made from – there are a few options available. Let’s take a closer look…

What are egg cartons made of?

Egg cartons are, generally, made of three different materials: pulp, foam or thin PET plastic. Due to their similar design, all of the materials do an egg-cellent (sorry…) job of protecting the eggs in transit. Each come with their own benefits. Whilst pulp and foam are inexpensive to make, the thin plastic variety allow consumers to see the eggs clearly in-store.  

Are egg cartons biodegradable?

A material is biodegradable if it can be broken down naturally by micro-organisms. Out of the three main types of egg cartons available, the pulp version is the only carton that is biodegradable. It will do so pretty quickly too – in ideal conditions, you can expect it to decompose within a matter of weeks.

The others, if they end up in landfill (which is highly likely for the foam variety – they can be recycled but is not commonplace) will be there for many, many years. They may well outlive you! It is likely that all the foam and plastic egg cartons that you have EVER sent to landfill are still there. Pulp cartons if sent to landfill, although not ideal, will not remain there for too long.  

Are egg cartons compostable?

Composting is a great way to dispose of organic materials – as well as being kind to the planet, you can also produce a wonderful, nutrient-rich fertilizer for your garden. Many people think that anything that is classed as biodegradable can be composed, but this is not the case. The terms biodegradable and compostable are not interchangeable. As well as being biodegradable, the item must also be able to contribute to a nutrient-rich final product – and not add any harmful chemicals.

Luckily, pulp egg cartons can be composted – and they, along with other paper-based items, make a useful addition. Composting items fall into two distinct categories. They are known in the composting world as ‘greens’ or ‘browns’. ‘Greens’ are nitrogen-rich items such as food scraps. ‘Browns’ are carbon-rich – they include items such as dried leaves and pulp egg cartons. Although paper/card in general is not the most nutrient-rich material out there it contributes to the carbon side of the carbon/nitrogen mix whilst providing structure and allowing gaps for air to circulate. It also soaks up excess moisture – often the culprit of a smelly pile! Your neighbors will thank you.

To maintain a healthy pile, you should have a mixture of both types of material. Too many browns and you could end up with an ant-infestation and a slowly composting pile. Too many greens could cause excess heat and an unpleasant odor. It is a delicate balancing act. Different ratios are suggested by different sources but a 1:1 ratio should work well. It is a lot simpler to manage too – and less daunting for beginners. Every compost pile is different though, and you might need to do some tweaking as you go. Due to the ratio requirements, you can’t just throw anything into the pile – but you don’t need to sit down and do complex math either.

Observing the pile will give lots of useful clues.  If you are new to composting, we have answered some of the most common questions asked by beginners here.

Considerations when composting egg cartons…

As far as composting goes, pulp egg cartons are on the easier end of the scale. Like other items, it helps if the egg carton is cut/ripped into small pieces before being added to the pile. Although not strictly necessary, it will speed up the process. Smaller pieces can also be mixed throughout the pile spreading the benefit of its moisture wicking properties.

Also, be mindful not to add too many to the pile at once. This could result in too much carbon in the mixture and will disturb the balance. Breakdown in your pile would likely slow down. But luckily pulp egg cartons are eco-friendly all-round – stick the rest in with your other recycling or use it for other garden activities such as germinating seeds.

The bottom line

Out of the three main types of egg carton available, the pulp version is the only egg carton type that is biodegradable and can be composted. It adds much needed carbon to the mix, and an element of structure to the pile. Although not biodegradable, the plastic version can be recycled – making it a decent choice in terms of eco-friendliness. Our advice?  Avoid the foam version where possible. Not biodegradable or, generally, recyclable. Steer clear!