I'm looking to grow some plants for Chirp. Ideally, something I could let him play on/in, munch on, etc. Something easy to grow and tough to kill. I have a big plastic tray that I could fill with eco-earth (coco coir), and sprinkle with seeds. Could I just take some millet and sprinkle it? How about Chirp's seed mix (millet, tricolor quinoa, flax, kamut, sesame)? Any input is appreciated!