Want to keep cats off your garden? Of course, the easiest way is to lay a wire net across the ground, supported by bricks. Cats won't step on it. But if you have no netting, one of the best organic gardening ideas is to toss prickly stems like bramble or rose clippings around the plants.
Other organic gardening tips to repel cats are to post sticks steeped in garlic paste, chili oil or chamomile essence around your beds. You could also grow French marigolds (Tagetes patula) which have a strong odour. Or lay cordons of garam masala, curry powder or other species. Cats hate strange fierce scents.
Alternatively, you could take some hot chili pepper seeds and steep them in olive oil for several months. Soak cardboard strips in this fierce cat repellent and put it about your seedbed or most precious plants.
You can even mix this strong-smelling oil 1:5 with water plus a little washing up liquid and apply it directly to your plants. Not only will this deter many insect pests but cats will also keep clear.
The simplest cat repellent is citronella oil, available at health food stores. You need just 100 drops of citronella to a pint of water. Scatter it daily around your garden till the cats learn to keep off. A quick substitute is fresh lemon or grapefruit peel.
An idea that's hardly organic - but it works - is to sink small plastic bottles about the plot with a few teaspoonfuls of ammonia in them. It's harmless to cats because they won't come within ten paces of that strong smell.
You can make a more elegant cat repellent that lasts for several weeks from a screw-top plastic bottle. Take off the cap. Fill the bottle with old nylon socks, or glass wool, or any absorbent substance that's inert and won't rot. Pull out a piece of this so it emerges from the bottle as a wick. Fill the bottle with any of the strong-smelling fluids suggested here. The bottle will protect its strong smelling contents from the weather and a few of these little bio-repellents, buried or hung about your garden, will repel even Tom and Jerry.
Repel cats this way - if you dare
Organic gardeners have reported good results by setting out plastic sealed tubs, perforated at the sides, containing dog faeces. This idea is not for fastidious gardeners but cats will scat! Of course, you wouldn't use the dung of a meat-eating animal directly on the soil, even around a flower bed. It poisons the soil and can lead to serious illnesses, not least among children.
A proven cat repellent is the urine of tigers, lions or any 'large cat'. It banishes all warm-blooded pests. If you're lucky enough to live near a zoo, you need only ask.
Cats can be a nuisance if you have a bird nesting box. Simply grow some thorny thing like roses or brambles around the post or tree.
Another natural gardening idea is to obtain a large metal drum that once held cooking oil or food products. Slice it into a sheet and wrap this shiny, slippery metal around the tree or post as a collar. Cats can't climb that; nor will squirrels or small boys.
All these repellents are harmless to cats, dogs and beneficial insects. Just keep inquisitive children away from the ammonia bottles!