Tunnel Watering Systems

Tunnel watering systems are designed to provide overhead irrigation to polytunnels in nurseries, market gardens and garden centres. Overhead spray lines produce a fine and even mist spray over the entire area of the polytunnel, watering everything inside the tunnel with a gentle rain-like spray.

One or two watering lines are used, depending on the width of the polytunnel. Single line irrigation systems use a spray line strapped to the centre ridge line of the polythene tunnel.  Twin line systems use metal straining wire to suspend the PVC irrigation line from. The pipe is pre-drilled to accept sprinklers, with flexible down tubes bringing the spray nozzles to a lower position to reduce ‘bounce back’ of spray off the tunnel sides. A small weight keeps the sprinkler in the vertical position, this can easily be brushed out of the way if it is at head height.

At the base of the downtube a drip-stop valve, which shuts when the watering finishes, ensuring the watering lines are kept full of water for instant start-up. The highly uniform sprinkler nozzles use much, much less water than the old Dutch-pin nozzles and provide watering levels similar to natural rainfall. Computer design ensures high coefficients of uniformity throughout the tunnel.

Tunnel Watering Systems can be automated if required, allowing the irrigation to be done early in the morning when evaporation rates are low and staff have not arrived on site.