Cat craving your green houseplants?

I came across something wonderful for our kitties. Oat grass. I bought a packet of seeds off of Amazon, with shipping they were around $4-5 (a bit high, I know). Within a few days they were sprouted and growing strongly. I didn't keep track of how long I let it grow before offering it to the boys, though I'd guess maybe two weeks. The cats adored it as soon as it was brought in. They both began eating right away. I assumed that the plant fiber would create surprise hairball-goo-piles all over the place. But we only encountered it once and it was shortly after one of the boys ate so I figured one of them just ate too fast... or much. As the grass got taller and older they both began to climb into the pot and lie down in the grass. We had no problems as far as the cats digging in it or using it for a potty. Love, love, love this for kitties! Now to find it for a much better price so I can plant it regularly. Oh, I wanted to note that I would bring it in for the cats to eat only for a few hours at a time then would return it to outside. Didn't want the novelty of it to wear off.