If this summer has demonstrated anything, it is our dependence on water being readily available to plot holders. Prolonged spells of dry weather have meant that frequent trips to the water troughs were a necessity for most. We are lucky on our site as we have the luxury of mains water being available throughout the year. I’m often reminded when reading about other allotment sites, that not all of them provide water for their tenants. Any water used on those sites either needs to be harvested or brought onto the site from elsewhere. But having easy access to water as we do, doesn’t necessarily mean we should take it for granted. We all need to pay for it through out allotment rent and so logic says if we can reduce our dependency on water piped in from the mains supply, then it can only be a positive thing. And then of course, there are also the benefits of using rainwater on your plants instead of treated drinking water.
Looking around the plots on our sites, many people have a water butt or a barrel next to their shed or greenhouse which is great thing to see. Guttering kits for sheds and greenhouses are common and easily obtainable. But what about those people who choose to use polytunnels? If you spend enough time scouring the internet to look for ways of collecting rainwater off polytunnels, you will find a plethora of different ideas that people have devised to do just that. One of those ideas I’ve taken on board and tried out with some good success.
By their very nature, the flexible walls of polytunnels present a challenge. Without doing some structural modifications, you have nothing to attach a length of traditional guttering to and the shape of the plastic covering bows in and out around the frame and can also move around in the wind. The solution I’m testing this winter costs comparatively little, takes around 15 minutes to put together and has already produced some good results.
The Materials
- Flexible guttering for a motorhome or caravan
- Polytunnel repair tape
- Water butt
- Electrical tape
- Short piece of plastic flexible pipe
The flexible guttering is readily available online, usually available in lengths of between 3 and 5 meters. It has a ‘J’ shaped in profile and usually comes with a self-adhesive strip along its length.
The Install
The install couldn’t be simpler, but I just needed to think of a couple of things beforehand. Afterall, once it’s stuck into place, you might not be able to move it again easily, especially if the adhesive on the guttering or the tape is particularly strong.
Once the water butt was in place, the guttering is simply stuck to the wall of the polytunnel, starting at the low point by the water butt and gradually increasing in height along the wall. Before I attached mine, I marked out the location of the guttering using a string and marker pen first. It’s useful to have someone on the inside of the tunnel when sticking the guttering into place so they can apply equal pressure from the inside as you press the self-adhesive guttering into place from the outside.
The adhesive on the guttering should be strong enough to hold the guttering in place to start off with. But, for added security, and to provide a better lip for the water to travel into the guttering, I used the polytunnel repair tape to stick the guttering onto the plastic wall.
Back at the water butt end, I trimmed the guttering a little to fit it into the plastic pipe and then secured into place using the electrical tape.
The end result means that I now have a gutter running along most of the length of one side of the polytunnel giving me a collection area of around 3.5 square meters. So far, this has proved to be very effective, considering the relatively small amount of rain we have had since I installed it. Over the winter I intend to add a second length on the opposite side, feeding into a second water butt.
This system, added to my existing IBC tank should allow me to collect around 1240 litres of rainwater. With another water butt on the other side of the polytunnel, that should bring me up to just under 1500 litres, or 1.5 cubic litres. I’m waiting for an opportunity to buy another two IBC tanks over the winter, and I have another plan for collecting rainwater into those. But that will have to wait for another future article.