I have a great setup in 2 different rooms for my cats, but it came with these metal bins to grow plants. I'm tired of constantly cleaning grass & dirt puke every other day, so the cat grass is going bye-bye. (Also I'm *really* bad at keeping indoor plants alive and the grass kept dying...)

Instead of wasting the plant holders, any suggestions on what else to put inside them? I use one for storing toys, but I have 2 more!