I love cats but hate their deposits and have tried lots of things over the years. My back garden isn't too bad due to having my own cat who has his own 'patch' which I check over daily. He also has a litter tray indoors. Out the front garden is a different matter, every cat in the neighbourhood thinks it's a large litter tray...and it's only a small front garden!...I've tried all the proprietry cat off, and pepper dust and all sorts. Citrus peel works for a short time...it also attracts slugs and snails so you've got a dual purpose product there! The thing I've found works best for me is MOTHBALLS. Cats can't stand the smell as it is a really strong camphor, and they leave the borders alone. All right, so they're little white balls, but they can have a sprinkling of soil over the top to disguise them, they work for a month or two, depending on the weather, and they're cheap to replace, they work for me!