Yes, you CAN water a polytunnel during a hosepipe ban – and not just with watering cans, either. While hosepipes themselves cannot be used to water any garden during a ban, soaker hoses are fine because they count as ‘smart watering’. In enclosed spaces such as a polytunnel or greenhouse, they’re great. And, best of all, you can attach one to the mains water supply, completely legally, so long as you include both an in-line timer and pressure regulator.
Current reservoir levels are already lower than at this time during the famous drought of 1976, and the hosepipe ban is likely to be in place for a long time. If you don’t fancy the idea of spending all your gardening time slogging back and forth to the polytunnel with a watering can, a soaker hose or two will do all the work for you while you get on with some ‘proper’ gardening.
Or, of course, you can just lie back in your polytunnel hammock sipping mint juleps, thinking about the lovely watering all your plants are getting.
If your mains supply is some distance from the polytunnel, bring it closer to the site using rigid (i.e. hard plastic or metal) pipes. Rigid pipes, also not included in the ban, are much better than hoses because they don’t affect flow or pressure so much.
Likewise, if you have several beds, use lengths of pipe (rather than hose) to bridge the gaps between them. If you are using several soaker hoses, a ‘Y’ connector is perfect for regulating the supply between them, so you don’t have them all running at once.
Watering a polytunnel with stored water
Many soaker hoses need 1 bar of pressure to work well, so if you want to use stored water instead of mains then make sure the soaker hose you buy will work at low pressure. Oddly enough, you still need a timer and pressure regulator for this kind of supply to be allowed under the ban. The pressure regulator in this case is probably unnecessary, but the timer is still a good idea – after all, if you go to sleep in your hammock you might wake up to find all your precious water is gone.
Technically, you can still use a hosepipe to fill a watering can – but only if it’s a ‘short length’ – and nobody seems to have defined exactly what ‘short length’ means. The ‘old cistern’ method fills a watering can much faster than a hose, anyway, and if you can find one and hook it up to an outside tap it will save you loads of time. Or, you can position a water butt beneath the tap, which also works.
Other ways to prevent water loss in a polytunnel
A thick mulch will help prevent water loss from the surface of the earth in a polytunnel, which in turn means shallow feeder root systems have more growing space space available. Plenty of organic matter, dug in before planting, also helps to retain moisture.
Some plastics leach chemicals into water
Water butts and water tanks are great in times of drought, but – and this is seriously important – make sure they won’t contaminate the water stored inside them. Some plastics leach chemicals into water especially when warmed by the sun – plastic rubbish bins, for example, are not manufactured with the storage of drinking water in mind. When you eat the vegetables, that water is going to end up inside you. So only use tanks and butts that were intended to hold drinking water, and try not to park them in full sunlight.
Remember to check your local water suppliers website for confirmation that ‘smart’ watering with soaker hoses is permitted in your area.