Compostable plastic bags

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Odsox
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Compostable plastic bags

Post: # 292527Post Odsox
Fri Feb 22, 2019 4:20 pm

Just recently one of our local supermarkets has been dishing out compostable bags at the checkout for soap and other smelly stuff to keep separate from food, also for double wrapping fresh meat. Then a couple of days ago one of my radio magazines was delivered in a compostable bag.
So as I knew nothing about such things I thought I'd better Google "compostable bag" to see how it all works.

Well from what I could understand from the various sites is, to break it down into it's constituent parts (potato starch & water) it needs either 50°C or ultra violet light, or both.
Now my composting skills are non-existent, I just chuck our kitchen waste "as and when" and when the bin is full I leave it for a year, and by then it's usually a nice brown earthy consistency.
But it would never get to 50° and certainly no ultraviolet light would get into my compost bin, in which case it would never break down.
As we don't have a bin lorry (landfill or otherwise) and as it states NOT to add it to plastic recycling, it appears that although it sounds like a good thing, there is no way I can get rid of the damn things.
Other than learn the alchemy of aerobic composting ..
Tony

Disclaimer: I almost certainly haven't a clue what I'm talking about.

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Re: Compostable plastic bags

Post: # 292528Post Green Aura
Fri Feb 22, 2019 4:31 pm

I think hot composting probably gets higher than that.

https://www.permaculture.co.uk/readers- ... ot-compost
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Re: Compostable plastic bags

Post: # 292529Post Flo
Fri Feb 22, 2019 7:26 pm

I've met those bags. They don't work on normal allotment composting unless you have the time to do the full thing on that permaculture link. You have to be very dedicated to do hot composting - you need time and space. It's a case of time and space as much as anything on yer average plot mind. And no I didn't get them to rot down.

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Re: Compostable plastic bags

Post: # 292530Post Odsox
Sat Feb 23, 2019 9:25 am

That's the reason I've not tried to hot compost.
According to GA's link you have to wait until you have a cubic metre of material before you start. Apart from grass clippings, who has a cubic metre of kitchen waste in a sensible time frame?
I have tried composting grass clippings, no problem there with the amount but I had a problem with the "brown" material. The only thing I could think of was shredded paper, and there is no way I could accumulate a the same amount of shredded paper to match even a small quantity of grass.
Tony

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Re: Compostable plastic bags

Post: # 292531Post Green Aura
Sat Feb 23, 2019 9:46 am

I think you can do smaller amounts in things like those daleks, but as they're usually made of plastic it sort of defeats the purpose.

I saw a picture of a new shop darn sarf somewhere proudly proclaiming it's a plastic bag free, bring your own receptacle affair. Great idea but all the holders/tubs etc in the shop were made out of plastic.

I understand there's a difference between single use and these long term things but they stil break and need disposing of.

Anyway, back to your bags. Could you bung them in the oven for a while? Maybe the process just needs a kick start rather than constant heat. It might be worth a try.
Maggie

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ina
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Re: Compostable plastic bags

Post: # 292532Post ina
Sat Feb 23, 2019 12:03 pm

Somehow, plastic you don't want to degrade, does very easily; and the stuff that's supposed to be compostable, isn't! Just this morning, I tried to pick up a bucket that's been out in the garden for at least a year, ex-fat balls, and it crumbled in my hands. I have loads of bucket standing around to collect water. But some just don't make the grade... I also remember the allegedly bio-degradable carrier bags that the Coop had years ago. They degraded so easily that you could only use them a couple of times before they ripped apart. I have some plastic bags that have been around for almost 20 years! Isn't that better than "enforced" single use? (Can't actually remember the last time I needed to get a bag when shopping, but they do turn up somehow, mostly with stuff from friends.)
Last edited by ina on Sun Feb 24, 2019 9:31 am, edited 1 time in total.
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Re: Compostable plastic bags

Post: # 292533Post Skippy
Sun Feb 24, 2019 9:23 am

I've had my share of plastic buckets falling apart. Mostly they are reused and have formally contained paint , tile adhesive , lime putty and the like and are aquired through work but as pointed out whether single or multiuser they are still plastic. Awkward thing really is with a lot of paints being water based nowadays the plastic tubs are much better than metal. Dulux tins seem the worst with a terrible habit of rusting on the inside.
Anyway gone slightly off topic . Does anyone have any experience of those compostable glasses that are used to serve beer and other drinks at festivals and large events?

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Re: Compostable plastic bags

Post: # 292535Post Weedo
Sun Feb 24, 2019 10:19 pm

I recall this discussion on another thread a while ago. Plactics are inherently environmentally stable but many are now designed to break up (not break down) with exposure to ultraviolet light. Some have starch added to the polymer to speed the break up process.

We have recently been shifted to a green waste system that included being issued with little plastic bins and compostable liners intended for kitchen scraps. If any "wet" scraps go there the little bag breaks down in a couple of days. Odsox, you are mostly correct in that the avegage home composting won't get warm at all unless carefully managed (also on another thread somewhere?) You could try putyour bags in some hot water before composting.
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