I have been unable to find details of plant food I can use that won't harm my cat (who occasionally has a chew on them). I hope someone can answer this. Thanks

Welcome, Moiramac! Are these indoor plants you are wishing to feed? I should think most organics would be safe. Compost tea, perhaps?

And have you checked to make sure that the plants themselves that kitty is munching on are safe around cats? There are any number of lists available online. Here's one of them:
http://cfa.org/Owners/CatCare/...

there should be a number or website listed on the package you can call. Or call your vet and ask them. I would say when in doubt, the answer is no. It isn't worth it. Just switch to a liquid feed or you can put some barrier down over the plant food, like a small rock or something so she can't access it.

Ah, yes. Is kitty munching on the Plants or on the fertilizer?

The vet told me a few week ago that it is not a good idea to let your cat drink the water that can collect in those bowls under plants. Ours go to great lengths to get to it.
He said it is determined by the plant but just to be safest to not have them drinking the water.
Never hurt them but I thought I would let you know.

Wow. Never even thought of that. Good to know!