WHEN Kenchester Water Gardens applied to become members of the Heart of England Tourist Board, they were told that to achieve membership they had to welcome 10,000 visitors in a year. Initially this seemed a daunting prospect, but was rather less so after they counted 4,000 vehicles through their gates the following weekend.

Visitors now come to the water gardens from all over this country, and further afield. A significant amount of trade is not local but comes from South Wales and Gloucestershire, with one regular client coming down from Edinburgh. Last year, a party of scientific officers from New Zealand visited, and the International Water Lilies Association held its Symposium, bringing in 250 delegates from all over Europe and America.

All this is a far cry from the day 18 years ago when the doors opened on the business at their old Kenchester headquarters, where there was car parking space for just four cars. Nowadays, proprietor Malcolm Edwards employs 20 staff on the six acre site at Lyde where there are over 400,000 water plants, 136 varieties of water lilies and 80,000 cold water fish for sale.

Edwards himself came into the water gardens business by a rather circuitous route, having worked in engineering, ultrasonics and in retail management. He then started to design gardens, and combined this with an interest in koi carp. ''Water gardening was not very well understood when we first started,'' he said, ''not having altered appreciably since the turn of the century, so we were very fortunate in that we were able to develop in our own way prior to the boom in gardening centres.

''Now there is a huge worldwide interest in water gardening, to the extent that we have a

wholesaling division which supplies over 100 garden centres.'' Malcolm Edwards says that many local people take advantage of the dining facilities at lunch-time.