A polytunnel concentrates everything — heat, humidity, and the cost of getting watering wrong. Hand-watering a commercial tunnel eats hours every single day, and hose-watering never feeds the far end like the near end.
We design and install polytunnel irrigation systems for commercial growers across the UK… drip, overhead and fully automated, sized to the tunnel and the crop rather than sold as a kit.
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Drip lines along the rows. The default for most polytunnel crops. Water goes to the roots, the leaf stays dry — which in a warm, still tunnel is your best defence against botrytis and mildew. Drip also uses the least water and pairs with fertigation if you feed through the line. Built on the same engineering as our drip irrigation systems.
Overhead lines and misting. For propagation, leafy salads and crops that want humidity, a properly designed overhead run gives even coverage the length of the tunnel — the discipline is the same as our overhead sprinkler systems, scaled to a tunnel’s geometry.
Many growers run both: drip on the cropping rows, mist over the propagation bench. Zoning makes that one system, not two.
A single tunnel is a straightforward install. Ten tunnels off one supply is a design job — mainline sizing, pressure balancing, zone valves and a pump and filtration set that holds up at peak demand. If the supply itself is the limit, water storage fixes the bottleneck as part of the same project.
That’s the work behind our soft fruit irrigation project, where evenness across rows translated directly into evenness in the crop.
Each tunnel waters to its own crop and schedule from that single supply. Soft fruit is the classic case — table-top strawberries, raspberries and blueberries all run on drip with fertigation, exactly the system behind that project.
An automatic polytunnel watering system — timers or sensors driving zone valves — takes the daily hand-watering off your workload entirely, and it waters at the right time of day whether or not anyone’s on site. For most commercial growers that’s the fastest payback in the whole system. For a hobby tunnel, honestly, a simpler setup often does the job… we’ll tell you which you are.
A polytunnel isn’t a small greenhouse — it heats faster, dries faster and ventilates differently, and the watering design has to respect that. Long runs need pressure-compensated drippers so row-end plants get what row-start plants get. Summer demand in a tunnel can be several times the spring figure, so the supply is sized for July, not April. And because tunnels are often on field sites with modest water supplies, filtration and storage do more of the work than they would on a mains-fed glasshouse.
That’s also why we design the water source into the system rather than around it — tank-fed, borehole or mains, the tunnel should never outdrink the supply on a hot day.
Uneven watering down the run is the most common fault we’re asked to fix on existing tunnels — and it’s exactly what properly specified pressure-compensated line prevents.
Most commercial tunnel growers end up fertigating — feeding through the drip lines. If that’s now or later, we design for it from day one: the right injectors, the right filtration, and lines that dose evenly along the full run. Retro-fitting feed to a system that wasn’t designed for it is possible, but doing it from the start is cleaner and cheaper.
Family-run, Lancashire-based, installing across the UK and internationally. We grow our systems from design first: crop, rows, supply, then hardware. And the person who designs your tunnel’s system is the same person you’ll speak to if you ever have a problem with it.
And we’re not only for large growers: single tunnels, market gardens and multi-tunnel commercial sites all get the same design process.
Tell us what you grow and we’ll design the right system around it. Call Simon on 07881 271 117, email simon@sitetech.uk, or get in touch to arrange a design visit.
Drip lines for most soil or container crops; overhead or mist for propagation and leafy crops. The tunnel’s length, water supply and crop decide the detail — that’s the design conversation.
Yes, with the right pump and filtration. Tank-fed systems are common where mains flow is poor… we size storage so the tunnel never outdrinks the supply.
Every job is different, due to the size of the tunnel, the crop and the equipment used, so we design first and quote the actual system — and show you the specification before you commit.
A single tunnel is a quick install; multi-tunnel sites take longer. Either way, the work is planned so the growing keeps going while we’re in — we’ll give you a timescale with the design.
