I was just searching for instructions on how to make a nice Bday card for a friend and came across:
They come folded into what looks like those tourist packets of a set of postcards, from which you slide out the main card and unfold. There is a hidden PVC tray with a paper board to use as the growing medium. It comes with cress seeds which are easy to sprout and yummy to eat. They say a Postcarden should last about 2 weeks and is fully recyclable.
It's made in the EU and there's only one US distributor: B5+10 Postcarden who's selling it for $12.95
If only it weren't too late to order it for the Gin Master's Bday!
...I shall have to try to make my own...mwuahahahahaha......