Feb 08

Compostable Bags

Compostable bags are made from organic materials and break down like leaves or garden waste in the compost heap. They have become popular in recent years as more people are home composting and with so many Councils collecting organic waste.

Small compostable bags are used in the kitchen for collecting organic waste. That might be peelings to go on the compost heap or food waste for processing with the local Council. Larger bags can be used outdoors to hold garden waste or line wheelie bins.

Types of Compostable Bag


Paper bags can be used indoors to collect kitchen waste and outdoors to line the wheelie bins and free standing. Compostable paper bags need a high wet strength and for this reason recycled paper is not used in compostable paper bags, only virgin resources.

The wood used to make the bags has a longer fibre length which gives more strength to the bags that would be achieved from recycled paper. A high wet strength is required because of the moisture associated with organic waste.

Corn Starch

Corn starch bags are made from bioplastics. Instead of using petrochemicals, corn starch is used as a source of polymers for the product. In Europe, compostable corn starch bags come with a ‘seed’ logo. The seed logo ensures the bags have passed European Standard EN13432 which means they break down to compost in 3 months under test conditions. Other biodegradable corn starch bags are available so it is important to make sure they have the seed logo.

Corn starch bags can be used to line kitchen caddies and are commonly collected by Councils for processing with organic waste. They are available for dog waste and also as bin bags though they don’t break down in landfill.



Biodegradable, oxo-biodegradeable, hydro-biodegradable, photo-biodegradable, water soluble… There are many labels given to different types of bags to try and big up their green credentials. However, it is only compostable bags with the seed logo that are suitable for home composting and as kitchen caddie liners.

Home Composting

There have been complaints that compostable bags don’t decompose as quickly as other compostables on the home compost heap. That may cause problems so gardeners should give them a try before committing to their use.

Council Collections

Some Councils have experienced problems with people using the wrong bags with their organic waste. Many will collect compostable bags but some won’t to avaiod contamination.

Environmental and Social

If the reason you are using compostable bags is because you want to be kind to the environment there are a few things to think about. The paper bags are used from virgin resources. Though the woodlands may be managed, there is an environmental impact to be considered.

Corn starch bags are made from bioplastics. They degrade much more quickly than conventional plastics, however only under the right conditions. Once in landfill they don’t break down as there is no oxygen available so are no better than conventional plastics.

Corn is the raw material for corn starch. With millions starving in the world there are moral issues about using potential food stuffs to produce plastics.


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