It is a worry, I agree. I wash my lettuces obsessively because I know what the neighbourhood moggies get up to in my garden when I'm out at work. While it is clearly not advisable to eat food with urine on it, cat pee doesn't pose a serious health risk. It's “No 2s” you've got to watch. Cat poo can carry a disease called toxoplasmosis, which is particularly dangerous to pregnant women and those with impaired immune systems. To reduce the risk, wear gloves when you're gardening, or if, like me, you end up snapping seedlings unless you use your bare fingers, wash your hands thoroughly when you come in.

Celia Brooks Brown, the cookery writer and allotment owner (see her blog at www.timesonline.co.uk/realfood , says cats pee mostly on clear ground, so avoid leaving bare soil where possible. There are also steps you can take to deter them, she points out, from the organic method of laying spiky prunings on the soil, to less green battery- powered machines that emit sounds cats don't like (www.deteracat.co.uk; £28).

My favourite method is the Silent Roar pellets that have been soaked in lion dung (www.crocus.co.uk; £8.99). They are supposed to scare cats away since they assume their fearsome relatives have already claimed the territory.

Last year I tried sticking dozens of barbecue sticks around my vegetable plot and winding cotton between them to create a maze-like structure. It kept them away for a while, until a couple of kittens decided it must have been constructed for their entertainment and started rolling under the cotton, flattening my lettuces.

How Green Are My Wellies? by Anna Shepard is out now (Eden Project Books, £14.99); www.timesonline.co.uk/booksfirstbuy

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