PolyTunnel Watering

Dear Martin

We have a polytunnel 30x14 ft, so 2 beds about 5ft wide each, the length of the tunnel, plus a load of raised beds and small greenhouse. We also go away for weekends on babysitting duty, so need a watering system that will operate happily by itself. The water source is a tap that is fed from a well with reasonable but not high pressure, unless we have a drought of course!
We are thinking soaker hose as being a reasonably economic product, but I notice that you also have a hose with built in drip points, but it seems more expensive to cover the same area and would it need a timer?
Wasn't sure from the info provided whether the 50cm mentioned for the soaker hose was the full width, ie the soaker hose covers a width of 50cm, or whether it was to each side, ie 100cm. It looks like 100cm, in which case I suppose 5ft width would need 2 lengths of pipe, or try it with 1 and see?

Kind Regards


Dear Nigel

Many thanks for your recent enquiry concerning a suitable irrigation system for your polytunnel and beds. You seem to have worked out the answer for yourself and I’d certainly agree that the soaker hose takes some beating for efficient water distribution from a low pressure source.

Just to confirm, water will spread around 50cm either side from the soaker hose in cultivated soil so when calculating the length of hose you will require, allow 1m between loops. It’s this spacing that makes the hose economically attractive as well as efficient and as the soaker hose is the same diameter as a standard garden hose (½”) extra lengths can easily be added if required as all off the shelf hose fixings are compatible; that’s connectors, joints, the lot!

So the soaker hose is certainly my recommendation – the drip feed, small diameter piping which forms the Raised Bed Irrigation Kit and other similar products really comes into its own in tight small spaces – and  I’d certainly try the minimum spacing to begin with. 

I trust this information is of help but if there’s anything else you’d like to know them please don’t hesitate to ask; many thanks once again for your enquiry and the best of luck with your growing - and irrigating - activities this year.