I just recently ordered the testudo seed mix from tortoise supply so while I'm waiting for it to come (and grow eventually) I just wanted to know which super market greens are ok to give more frequently than others and which ones aren't high in oxalic acid? I keep reading conflicting information of which ones are high and which are not. Most of my tortoises' diet consists of hibiscus leaves and flowers, opuntia cactus (which my hermann's won't touch ) water cress, kale, and spring mix (which I don't give them the spinach). I'm a little confused on what I read on websites and would like to hear what is safer to eat in higher quantities. Another reason I'm asking is because a little bit of greens lasts me a looooong time since my tortoises are so young and it ends up going bad which is why I don't buy so much of a variety at once.