Seed wise, I get mixed bags from the Shelled Warriors shop and I have a weed patch where I literally sprinkle them in and let them do their stuff. They're pretty good usually. I find the clover takes well as do any thistles, nipplewort and dandies.
In the spring I get lavatera seeds from Wilko, around 50p, sprinkle them in pots and they usually take and produce LOADS of flowers. I also sow nasturtium, pansies, nemesia, petunia, calendula, etc...
Look through the Tortoise Table Plant database
https://www.thetortoisetable.org.uk/.../#.Xcg0nNX7SUk and you'll find lots of flowers you'll recognise that are easy to sow and grow.
I have a lovely patch of plantain and each year let the seed heads disperse as and where and take them and rub them between my hands so they go in the weed patch and into the tort enclosures. It's a wonderfully hardy weed, fibrous and popular with the torts. It took a couple of years for the patch of plantain to really take hold but now it has it's brilliant and I can pick from it through the colder months too.
I wouldn't feed my med torts timothy hay. I (perhaps wrongly) assumed it was for larger species like Sulcata, Aldabra, Leopards, etc. I may be corrected here. I had a feeling it's not easily digestible for med torts.