Why use a clockwork timer

Two main reasons: (1) it saves you forgetting to turn off hanging baskets if they are not on the main line controlled by the battery-operated timer; (2) A clockwork timer is ideal for soaker hoses which tend to be used once a week, and then only in dry periods, for giving a good deep soaking to trees, shrubs and borders. So set it for any time from 5 minutes to two hours and it will turn the water off automatically.