I'll let you know if I ever figure it out

Are you tray watering ever other day and giving it lots of light?

No. My in-house grass dies under two weeks.

Late reply but. Grass doesn't live forever.

Also it really likes sunlight. It doesn't grow well in shade. If you ever notice outside it doesn't grow well in shaded areas.

Also needs watered.

I cover mine with plastic wrap to help keep it hydrated.

But again. It doesn't live forever. So don't expect to keep it alive forever like a house plant .

Also cat grass is wheat grass.

Hella cheap to buy wheat grass seed and it turns into grass in about a week.

I grow my own.