While watching the grandkids' swimming lessons we always have a cup of coffee served in cups which claim to be 100% compostable. To test this claim I took a one home, half buried it in the garden and photographed it every now and then over a three month period to see if the claim is realistic.
Not a fair test because standard composting conditions are much more vigorous - see note below. Yet after three months the cup was certainly well degraded. The composite photo below shows it at the start and after two then three months. The last photo was taken on December 19th 2019 so the ground was pretty cold and any biological activity would be slower.
I'm quite impressed because the cup has to contain hot coffee without damage but seems likely to sail through a standard composting test.
The next effort was a National Trust magazine bag made from a material which contains potato starch. Again, not a fair test for the same reasons but I thought the bag would degrade quite rapidly, the National Trust being so reliable on matters environmental hem hem. The two photos were taken about three months apart but I could see no degradation at all, although it did get a little dirty and that could suggest a small amount of surface degradation. Nowhere near as impressive, which for me was a surprise.
Compostable materials are materials that have been certified to break down completely into non-toxic components (water, carbon dioxide, and biomass) that will not harm the environment, given the right conditions. The time it takes for something to break down depends largely on the product itself and the composting conditions.
Some materials can decompose in your home compost (like loose tea leaves and apple cores) but not all compostable materials are suitable for composting at home. Bio-plastics (compostable alternatives to conventional plastic packaging like our tea temples) are fully plant-derived and fully compostable but they require higher levels of heat, water, oxygen and micro-organisms to fully break down than what your home compost can provide. For anything to be legally labelled compostable, it has to have been certified to break down in industrial (council) composting facilities within 180 days.
6 comments:
We normally line our little kitchen composter with greengrocer's brown paper bags. Lately I've been using those see-through ones as per your picture, which a newspaper gets sent in. (The Church Times. The C of E are even more woke than the NT!)
I hope I haven't got a garden composter full of dirty old plastic bags to sort out in the spring!
You probably ought to pour vinegar over it to set off a reaction but that would poison the soil... Go woke go broke
Here's a post from another publication, Mr H, which I think is relevant...
I've Just checked TWBC website and here's all they say about food waste: -
What happens to the collected food waste?
The food waste is taken to a local facility where it is composted using a natural process, which means it is safe to use as a soil improver on local farmers' fields. If you already compost at home, please continue to do so. You can use your food waste collections for any food that you do not want to compost yourself.
Answers on a Waitrose compostible bag, not to be confused with a similar-looking one from Twongos or Borrisons, Mazda or Widl (?), but which won't compost for a hundred years or so, and will clog up the environment even more than it does now!
I can imagine all our hard-working farmers doing high kicks when a pile of that sort of stuff arrives to cheers from the environmentalists and happy bunnies prancing all around - with plastic in their teeth...
Actually, Graeme, you're dead right, but it's cheaper to wee on it instead...
Wee for woke, and woke for wee, cha cha cha...
Weeing on your compost heap works as an accelerator, though you have to be careful you don't get nicked for exposing oneself in public !
Sam - if the bags are similar to the National Trust bags then they may test the efficiency of your composter. If if composts them well then it is probably pretty good.
Graeme - I expected the soil microorganisms to tackle the bag with no assistance as it is quite fertile and must contain a good mix of organisms. Not bag-loving organisms apparently.
Scrobs - wee on something from the National Trust? Is that even legal these days?
Wiggia - I use a jug - I mean I would use a jug if I ever did such a thing.
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