Jimlad9, why shouldn't we cat lovers read your thread? It's not as if we don't have the same problem with our own pets in our own (and other people's ) gardens! We love 'em, but we know they're not perfect.
I was listening to NPR (National Public Radio) last weekend and heard a couple of tips about safe cat-repelling during a program about gardening. Of course the host reviewed the usual repellent sprays with animal uring in them, but he was rather dismissive of them. However, he had two specific recommendations:
The first suggestion was to lay chicken wire across the entire flower bed and then cover it with a THIN layer of soil. This is supposed to prevent a cat from pooping there because its instinct is to dig deeper than that in order to make a hole to poop in (and also to cover it well). The plants, of course, are supposed to come up in the holes in the wire. The disadvantage of this, according to the program's host, is that the wire eventually rusts and has to be replaced. I imagine that if you're growing a large enough plant, the size of the holes in the wire could be too restrictive.
The other suggestion had me guffawing madly! It is a product called The ScareCrow. It's a water sprinkler that's motion-activated, PLUS once it detects the movement, it actually turns itself in the direction of the moving creature and then sprays a burst of water at it! This keeps you from over-watering as you might do with a regular sprinkler... and gives you the satisfaction of watching the thing swivel around to take aim at the offending cat, and watching the cat leap vertically into the air in surprise.
Most cats have enough intelligence that they will only need to be squirted once or twice before they decide to go poop someplace else that's drier. However, you may get the occasional thick-coated cat that doesn't mind getting wet (in which case, see the chicken wire plan).