Do Earthworms eat Compostable Packaging? Part 2

close up of a hand holding a partially composted hot cup

You may remember that last year we went looking for answers to the question: ‘Do Earthworms eat Compostable Packaging?

We were assisted by avid worm farmer, Luke Beart, who was composting some of our products in earth farms on behalf of the good people at LexisNexis.

Luke uses Red Wigglers, or Eisenia Fetida composting earthworms, to turn organic waste into high-quality, nutrient rich soil.

We learned that the earthworms were happily munching our Hot Cups and Sugarcane Bowls. And that while the worms could eat the thin layer of PLA that line our Hot Cups, our thicker PLA* Cold Cups proved too much for them.

This got us thinking about how the worms would manage some of our other products. Happily, Luke agreed to do some more testing.

So, we fed the worms some more of our compostables:

products lying in the worm farm crate products lying in the worm farm crate

Kraft Deli Box, a Paper Straw, a Coffee Cup Lid, a PLA Bag, a Wood Cellulose bag, a Wooden Boat, a Wooden spoon and a Muffin Cup.

How did these products go down with the worms?

They ate the paper and board products (deli box, straw and muffin cup) first. The wood cellulose clear bioplastic bag also disappeared after some time. These bags soften when continually in moist conditions, making them easier for worms to eat. But the worms didn’t eat the PLA* bag (which looks exactly the same as the wood cellulose bag). Most likely because these don’t soften. The coffee cup lid is also made from PLA, and wasn’t eaten either.

The wooden products (boat and spoon) broke down at a slower rate than the paper products. They are more dense and woody, but once they’ve softened up the worms are able to digest them.

The final verdict?

Earthworms do eat compostable packaging! Almost all of our products, including our wood cellulose bioplastic clear bags. But when it comes to PLA bioplastic, they’ll only eat very thin layers – don’t feed them anything thicker than a Hot Cup.

We were excited to see these results. It’s great to know most of our products break down in worm farms. We also weren’t too surprised that thicker PLA isn’t suitable. We know that it works very well in in-vessel compost machines and large-scale composting, where conditions allow microbial activity to create temperatures reach above 50°C. Read this blog post, and this one too, if you’d like to learn more.

If you’re wanting to do some worm farming of your own, you can contact Luke at lukebeart@gmail.com or 078 502 9450 to buy worm farms. Available in both Cape Town and Johannesburg

*PLA is a plant-based and compostable bioplastic made from corn starch. 

 

About Cassandra Gamble

Cass is GREEN HOME's Environmental Research & Communications Ambassador.
Her BSc (Hons) degree from the Open University (UK) focused on Environmental Science, plastic pollution and sustainable innovation.
She is dedicated to building waste-free and regenerative systems.