Sounds like a fun project! There is somebody on here (can't remember who..about a year ago) that makes teddy bears out of landscape cloth, stuffs them with container soil, and lets moss grow all over the things.

Could you just use cotton string? I have no clue. This is out of my league, but I'm interested in the answers you get.
I'm thinking of using some butcher's twine to wick a simple pot in the kitchen for my basil plant till it gets big enough to plant outside.

Post a pic when you get it finished!
Suzi

Just cut a strip out of an old cotton sock and use that.

I ended up using a short piece of clothesline and fraying both ends well. It seems to work.