Hi - I'm in the Northeast and on the tail end of what's been a brutal winter. I want to grow some grass indoors for my birds as well as provide them with some dirt to bathe in. I have planted grass in the past with some dirt I had from outside (everything now is frozen and covered with lots of snow) and topped it off with some organic potting soil. I noticed the birds did eat some of the fertilizer in the potting soil. Not thinking that was great for them, I removed the planter from their coop. What else could I use to grow more grass for them to munch on during the winter months and to dust bathe in (when some of the grass was eaten, a couple of them climbed in and started bathing! Too cute.) I wasn't sure what top soil really is and if that would be harmful to them. Or maybe the organic potting soil poses not threat to their health. Thoughts?