Earlier this year, Garden Organic looked into tea bags, in the light of our members' concerns about the presence of plastic used to make them. Many bags, even the organic brands, often include a small amount of polypropylene, which helps with the sealing and tying of the bag. This will not break down in the domestic compost heap, and indeed particles will remain even after commercial 'green waste' composting. Some brands use instead a polymer fibre derived from plant starch, called PLA. However, this starch is often sourced from genetically engineered crops, which will probably have been sprayed with pesticides. PLA will eventually degrade in the home compost heap, but it takes some time.
The new Clipper bags are made from plant-based materials (a blend of abaca, a species of banana; plant cellulose fibres; and PLA.) But their PLA is guaranteed to be from a non-GM source. And of course the bags are unbleached - so no nasty chemical residues.
See here for more information on Clipper teas.
And here below are our tea bag composting guidelines:
Best practice (ie first choice as organic grower): Use leaf tea, or buy bags which don’t have plastic in them.
Also acceptable (although not gold standard, this is still good practice): Empty bags, put leaves on heap and bags in rubbish collection.
Acceptable (as a one-off or temporary measure): Put tea bags on compost heap.