There isn't much cuter than watching a cat eat grass.  They like playing with it as well as chewing away at it.  That is why it is important to grow a pot of your own home grown cat grass for your kitty.  Without your cat greens, your cat quite possibly will chew any plants you have growing around your home even if potenially toxic. 

Even if they're eating the best cat food in the world, cats may need a little help with digestion. Tender green grasses help provide this assistance. Cats are actually biologically programmed to eat grass for this very reason. 

After planting your seeds, give them a growth period until sprouts are about 2" long before exposing plant to cat.  It is a good idea to have two pots growing so you can alternate.  If your cat binges on grass, put it out of reach and use it as a "salad treat" for your feline.