Judging by the number of cats in our neighborhood, my neighbors are all cat people. I don't mind cats myself, when they're not yowling at three o'clock in the morning, but I do mind what they do to my garden.
My garden is my pride and joy. It may not be the most beautiful garden in the world, full of flowers and their colors and scents, but it's a productive garden. During the summer months it's filled with tomatoes, squash vines, potatoes and onions. In the winter I cram it full of garlic, leeks, kale and spinach. I try not to leave any patch of soil bare for long, but that doesn't stop the cats from making trouble.
In the summer the worst they usually do is sleep on the plants and squash them flat. They usually recover from that, as long as it's not constant. In the spring they lie on my seedlings, and some of those don't survive the experience. But I can sow extra and fill in the gaps. It's in the winter that the cats are at their worst. They seem to think that any patch of bare soil, freshly dug over or not, has been left for them to use as a litter box. They leave me 'gifts' all over the garden, and they're not the kind of surprises I enjoy! It's worse when they cover them over, and I don't find them until my nose tells me there's something I should be looking out for....
Over the years I've tried everything to encourage the cats to 'go' elsewhere. First we put up a tall fence, all the way around the garden. It keeps out the old, fat cats that can't make it over the top, but there are always younger, more sprightly cats coming into the neighborhood, and it's doesn't stop them at all.
Next we tried the 'Scaredy Cat' plant, an herb that has a scent that cats don't like. I don't like it much either, but fortunately my nose isn't that close to the ground. But unless I grow Scaredy Cat plants all around the perimeter (and they're not hardy perennials) then they don't keep the cats out. The same is true for lion dung from the zoo, although at least it fertilises the roses.
A sonic device with an infrared sensor discourages cats from coming into the garden until the battery runs out, which doesn't take long. And they can sneak around it, it can't cover every line of approach into the garden. As security systems go, it's a bit like a sentry that can only face in one direction.
Since we can't keep them out of the garden, I've tried to stop the cats littering instead. Bare soil is mulched, but that's not fool-proof. I prefer organic mulches that improve the soil structure as they rot down, but the cats just find that ideal for burying their poop. Spiky twigs on the beds stop them crouching, but are just as much of a hazard for the gardener if you forget to wear your gloves.
When I clean up their messes I make sure to put down something with a strong smell, so the cats can't locate their toilet sites next time. I've tried orange essence, coffee grounds, sheep's wool and chicken manure pellets. They all smell strongly to begin with, but rapidly fade and lose their effect.
In desperation I made a little cat garden for them, at the bottom of the garden. It has everything a pampered kitty could want - a sunny spot, some shade, and lovely plants like catnip, cat thyme and Valerian. They don't use it, they'd rather wreck my vegetable garden.
Our 'live and let live' approach obviously isn't working, and so this year I'm declaring war. A sprinkler system with a sensor squirts anything that steps into its path. A water pistol on the kitchen windowsill is on hand to spray any cats that try to sneak onto the patio. I've tried to warn them, but they just won't listen. When we get back from vacation I'm bringing in the big guns - I'm getting a dog!