Cats have sensitive noses and don’t like strongly-scented plants such as geraniums, lavender, garlic, lemon thyme, lemon verbena, pennyroyal, or rue. So plant lots of these around the border of your garden and the perimeter of your yard to act as cat repellents.

Though I haven’t yet tried it, there’s one specific plant called Coleus Canina that supposedly helps keep feral cats, stray cats, and even dogs away. The plant is an annual but you can take cuttings and keep them in a frost-free place over winter. The plants need to be in fairly dry soil and planted every 3 to 6 feet.

As with all of these methods, people on the Internet report mixed results. Apparently, some of these animals have not visited the Internet nor read the instruction books.

Some of the following cat repellent scents can be expensive (because you have to apply them again after it rains), so how do you know where to place them for maximum results? Get a portable ultraviolet (UV) blacklight which can show you where the cat urine is. That’s the cat’s "territory" where you need to clean, hose down, and then apply your cat repellent scents.   (CONTINUED BELOW...)

Once you know where to apply them, sprinkle pepper flakes, crushed cinnamon, coffee grounds, used tea leaves, or cayenne pepper around your beds. Some of it will stick to their feet and they’ll lick it off when cleaning themselves. Some people have suggested that cayenne could be dangerous to the animal as they could get it into their eyes. Caution: if you have small children in your yard, there’s the possibility they could get cayenne on their hands and then rub their eyes.

Sprinkle essential oils around the borders: lavender, lemon grass, citronella, peppermint and eucalyptus. To save money, dilute them with tap water and spray onto the leaves of plants around the borders of your garden.

You may also want to spray some puffed rice or puffed wheat cereal with your cat-repellent oils. Put the sprayed puffed cereal into open containers and place them around your garden. They’re less likely to be washed clean of the oils when it rains and should last a little longer than spraying directly onto plants.

Some people have simply placed unlit citronella candles along the borders to their garden to act as a cat repellent. An advantage of the candles is that they may last longer and may not have to be replaced after rains.

Cats supposedly don’t like the smell of citrus fruits. So grind up grapefruit or lemon rinds or orange peels in a food processor and sprinkle it around the garden to serve as an organic cat repellent. It's also good for your plants and the soil.

I’ve also sprinkled liquid, environmentally-friendly, concentrated, orange-scented cleaners around the entrances to the yard and that did seem to help some but, of course, has to be reapplied after it rains. And your yard may be too big to make this practical.

Consider spraying old cloth rags with citrus air freshener or detergent and wrapping them around the particular plants you want to protect.

Vinegar. Spray it around the areas you want to protect. Repeat after it rains.

Moth balls (or camphor.) The moth balls last longer than the flakes. Cats hate the smell. They're a potent chemical cat repellent weapon in your chemical-warfare arsenal.

Caution: Some people have suggested the use of moth balls is not an environmentally-friendly solution as it will affect other wildlife and that it can cause liver damage to the cat. (Hopefully, the cat is not going to be staying around to smell that much of it.) But mothballs may also repel lady bugs and other beneficial insects. And they can be dangerous to squirrels, wildlife, children and your own pets.

These scent-strategies are often practical only for small areas, so use them in and around the flower beds, your children’s sandbox and other specific places you want to be cat-free.

Coyote/Fox urine. Yes, I know, it may be difficult to locate a willing donor but cats will avoid areas where scents of their predators are present. This works as a cat repellent because it’s a genetic thing: It’s hard-wired into their brains. Even if they’ve never been around a fox or coyote, cats instinctively sense fear when they smell their predator’s urine and will stay away.

Here’s a source: Shake-Away. (They also have versions for deer, racoons, and other animals.) It’s 100% organic and claims to be safe. It’s not a poison.

I know this product works because I’ve used it. But because it’s one of the more expensive cat repellents, it may be better to save it for use in a carport or sheltered area.

Outside, it has to be reapplied regularly after rains. (The merchants claim it will last a month but I think that’s overly optimistic.) You may want to try putting some of it in wide-mouth glass jars turned on their sides so that it’s protected from the rain. Put it in any areas of your yard which cats are using as their "litter box." One reviewer of the product suggested that "more is not better." Use it sparingly for best effects. Sprinkle just a little of it a couple of times a week in the same location (just as a wild animal might mark its territory.)

This fear of predators is the same reason some people have recommended sprinkling lion dung in your garden as a cat repellent. (It’s sometimes sold by zoos as Zoo Poo.) )

Cats are both ritualistic and territorial. It may take a few days for them to find a new bathroom but, hopefully, with the encouragement of your cat deterrent strategies,
they’ll find a new "litter box" off your property and you’ll be rid of them at minimal expense.

To encourage them to relocate, it may help to uncover and remove their feces from your flower beds, hose down the area, and then cover their scent with orange peels or the Shake-Away products.

Now, let’s move on to... Part II - Cat-Deterrent Stratgeiges - MECHANICAL