It's a fact of life with cats that you'll clean up your share of wet slimy hairballs, particularly if your cat is a long haired breed or sheds a lot. Cat grass will help this process along, especially if she eats a large quantity at one time. Your cat will NOT vomit every time she nibbles on grass, but if she does or if you see blades of grass in her vomit, it's probably a sign something needed to be unclogged. Consult with your vet for the best course of action.
There is no tried-and-true amount of grass that you should plant, but we recommend planting about a handful of seeds at a time. If you have multiple cats, consider giving each cat her own patch of grass so that there's no competition.
When it comes down to it, is cat grass safe? Yes, especially if you take care to buy the appropriate kit or seeds and, as always, keep an eye on your cat's habits and health. If you notice anything out of the ordinary, contact your vet right away.
Not all cats will eat cat grass (they are notorious food snubbers, after all), but many of them do. So why not offer some to your furry friend to see what she thinks? She just may love having a little garden all to herself.