I have looked into growing it ourselves, but it doesn't seem that easy to grow -at least buying it I know it will be good large heads like these. I wish we had known about it earlier in his life - his favourite things before that were red and yellow peppers (only little bits as a treat) - and cucumber, which he still loves, but also has as a treat. At least radicchio has quite a bit of fibre in it, which is good.Oh my goodness- that is what we will do for our tortoise for a Christmas present! So funny. Could you grow it in your yard? I'm going to look into that because we have a small garden. I tried some and it's so bitter, I'm surprised they like it so much.
That's amazing that your tortoise is 20!
Zola will be 21 in July, and we have had him since he was ! year old. If you are interested, you could look up Please welcome Zola in the introductions section - about last October ,I think, where I wrote a long description of his unusual life - he is wonderful.
Angie