Plastic forks stuck in the ground upside down, Popsicle sticks, wooden chopsticks and hot peppers discourage cats from entering a garden. French marigolds, rue plants, citrus, ammonia, citronella oil and dish washing liquid are other ways to deter cats from a garden.
Placing plastic forks, Popsicle sticks or wooden chopsticks seven to eight inches apart in the garden makes it inconvenient for cats to enter the garden. This method deters cats without hurting them. Alternatively, mix chili pepper seeds with olive oil, and allow the mixture to steep for several months. Soak cardboard strips in this mixture, and place them around the garden to deter cats. Mix a couple drops of dish washing liquid with a couple of drops of scented oil and add the mixture to a squirt bottle filled with water. Spray this on plants to deter cats from the area. Put 100 drops of citronella oil in a spray bottle and fill the spray bottle with water. Mist the garden every day with this mixture to repel cats. Cats do not like the smell of citrus, so spreading orange or lemon peels around the garden area deters cats. Plant rue plants or sprinkle dried rue leaves around the area to repel cats. French marigolds have a strong odor that cats detest. Growing these plants in the garden deters cats from the area.