Four Dispongeable Sponges were put into a compost pile on June 22, 2020 (photo 2, photo 3) – the pile was in full swing of decomposition, with microbes producing heat and steam from their activity. A search on July 15, 2020 located the sponges again, to track the rate of break down (photo 4), and same on August 7 (photo 5).

The Dispongeable Sponges were breaking down more slowly than other materials in the pile, mainly the horse and coffee waste, including paper coffee filters, and food scraps. We looked for fraying around the sponge edges, and also general degradation and shrinkage, and were encouraged to see some such progress.

More effective might be to shred the sponges before putting them in compost piles, in order to create more edges exposed to air and heat and moisture. Though extra work it might only require two snips with a scissors, and similar extra effort is required for eggshells and crab claws and avocado skins and the like, as well as for compostable trash bags, which also need to be shredded a bit for effective composting.

Cutting the sponges would make experimental tracking more difficult but was nonetheless executed by EarthBrew on September 12 (photo 6, photo 7). On September 21, the shredded pieces were moved to a new pile (photo 8) to continue their composting, and also so they would not be delivered with the now-ready compost from their original pile.

​The sponge pieces did show further signs of degrading and fraying, while not yet crumbling into friable tilth. Ninety days is a good gauge of an item’s compostability, as most items show nearly complete breaking down at this time in a properly turned and managed pile. In this sense, composting is different than biodegradability, which is a lesser measure but still good, and more than can be said about mainstream sponges. We believe that Dispongeable Sponges are in fact compostable, if cut in pieces.

Many commercial products whose packaging calls itself compostable, such as certain coffee-bean bags or trash bags, tend to add disclaimers that this requires an industrial pile, meaning not to be tried in home/backyard piles. Most backyard composting setups are not bringing the elements necessary for full and proper composting. But these elements are available, and backyard success does often occur.

As the two cuts to the sponge to quarter it should suffice for Dispongeable Sponge composting, the company can put the cutting instructions on its label and therefore not need a disclaimer that composting requires an industrial pile. EarthBrew recommends a label that says, ‘cut for composting’, perhaps with a simple scissors graphic.

EarthBrew Compost
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