Look at the Scarecrow motion detector water sprinkler. Battery operated; connected by hose to your water system...it can be adjusted to spray up to about a 30-ft distance. You'll want to set it up so you can get to the back of it to turn it off without setting it off first--unless you don't mind getting wet yourself.

I've been using a couple of them for a few weeks. They work reliably, although they haven't solved my problem...keeping a local tomcat from attacking my outdoor cats. I think they'd be great for keeping a cat out of a small garden area.

Kind of pricey at $89 each, but might be worth it, if it solves your problem. I got mine on E-bay for less.

Good luck!

Here is a link that might be useful: the manufacturer's site

As cats don't care for wter, the sprinklers might work. If you do an internet search, you may find them at reduced pricing. I have seen them from 49.00 and up.
Although it took weeks and lots of heated debates, the village did pass an ordinance, no outdoor cats unless they can be confined to your own yard. Since we are just outside of the village, that only helps slightly. However we do have wonderful coyotes which remove cats from the area. Maybe you could import a coyote or two? :-) Or at least threaten too. The only exposure to the outdoors my AMber gets, is the view from her window box. No need for her to be outdoors. Did you know that outdoor cats cause more allergies than indoor cats? Not surprising I guess.

Depending on the size of your gardens, this might be too laborious. When my kitty was testing out my indoor plants for litter boxes, I buried plastic forks facing up about 1/4 inch under the soil surface. He didn't like the feel on his paws, and I didn't have to see them.

Now that I have an outdoor lawn, I've found that he dislikes the compost pile that has biodegradable mesh composting near the surface. It is no good for digging.

If you are just trying to keep him out of the yard completely, go for the water.

Good luck

The cat will find another way around the water, purchase a cat trap, then take the cat to the humane society, Your info is confidental.Honestly it's unfair to you that you're neighbor is allowing thier cat to roam unsupervised. it is there responsibility to supervise there own cat period, you shouldin't have to landscape your yard around a cat that doesin't even belong to you.contact your local humane society tell them you are having issues with cats I'm sure they will tell you to trap it. by the way the domesticated cat won't kill the birds at your feeders to eat, domesticated cats kill for sport.(not eating what they kill)kill for fun.

My experience with the motion detector Scarecrow is that it kept busting my water hoses. I bought two, but no longer have them connected because they busted three, good water hose although I didn't have the water on that fast. It was very disappointing because I bought them to keep stray cats out of my backyard, and to spray whoever came into my front yard to steal fruit from my plum and avocado trees :-( Wish they would pass an ordinance here, but like even the one that dogs should be on a leash is not obeyed, the same would happen with containing cats to ones property.