worth having a look we used to grow them in bowls in the gh and outside and are very nice to eat for us and the torts, this site has a lovely selection of all sorts of different mixes etc and works out far cheaper than buying from the shops.
http://www.pennardplants.com/search....=&stype=&scat= we first saw them at a garden shows and the bowls of mixed leaves looked lovely they can all be cut and will regrow our birds also had them for breakfast. Theres even a tort mix on page 4.