Irrigation for Polytunnels

Designed for polytunnels, WaterMate uses sensors to deliver precise, weather-reactive watering. With precise soil watering rather than surface soaking, you’ll notice sturdier roots and fuller yields, as well as fewer fungal issues. Better yet, it’s all from a system that runs quietly in the background.

Why Smart Irrigation is Essential for Polytunnels

Polytunnels create a unique growing climate and have transformed the way people grow, but they also mean watering needs to be smarter, too. 

Inside a polytunnel, temperature, light, and humidity shift constantly, creating tricky conditions for consistent watering. Traditional methods like hoses or timers often lead to overwatering during hot weather or dry roots when things cool down, and that’s where a smart irrigation system for polytunnels can help. 

WaterMate is designed to adapt to your polytunnel’s changing environment, keeping your plants healthy without the stress or guesswork.

With sensor-based control and automated scheduling, our watering system for polytunnels responds to real-time climate data, rather than just a timer. It’s the smarter, more efficient way to grow, especially when you can’t be there to water daily.

  • Up to 80% Less Water Used

  • Targeted Watering = Zero Waste

  • Reduces Runoff and Overwatering

How WaterMate Works for Polytunnels

Polytunnels can be unpredictable - they’re sunny and humid one moment, cool and damp the next.

WaterMate takes the uncertainty out of watering by responding automatically to real conditions inside your tunnel. It continuously measures temperature and humidity, watering only when your crops actually need it. 

Once set up, your WaterMate will run smoothly in the background. If you ever need to, you can check, pause, or adjust watering schedules from your phone, giving you complete control, even when you’re away.

Whether your setup is off-grid or mains-powered, our drip irrigation system for polytunnels is designed for flexibility and reliability, making it ideal for the UK’s variable climate.

Buy WaterMate Pro Here!

Challenges That Automatic Watering Solves

Reduces risk of overwatering in humid conditions: Traditional watering methods often drench plants when the humidity is already high. A smart drip irrigation system for polytunnels delivers precise amounts of water, preventing root rot and wasted resources.

Helps prevent mould and rot in enclosed spaces: In a sealed environment, moisture build-up can cause fungal growth. Automated polytunnel watering systems keep conditions balanced, giving plants what they need, not a drop more. (Humidity sensors sold separately)

Adapts to fluctuating tunnel temperatures: Whether it’s a cool morning or a midday heatwave, WaterMate adjusts automatically. This automatic watering system for polytunnels ensures steady hydration across all zones, promoting consistent growth.

Ideal for growers who can’t water daily: Perfect for hobbyists or busy growers, our polytunnel drip irrigation kit maintains the right moisture levels, even when you’re away.

Here’s How to Set up Watermate

The Benefits of Automated Watering for Polytunnels

Switching to smart irrigation can make a visible difference to your plants, your time, and your results.

Manual watering in a polytunnel can be difficult. However, with a smart irrigation system like WaterMate, your plants get just the right amount of water, exactly when they need it. 

That means consistent growth, fewer watering errors, and more time for you to focus on growing rather than guessing. It offers peace of mind for busy gardeners, especially during hot spells or when the weather refuses to cooperate.

Beyond convenience, automated watering also leads to better results. By maintaining even soil moisture and avoiding stress cycles, crops like tomatoes, chillies, and lettuces grow stronger and healthier. 

Polytunnel-Focused Features

Sensors monitor temperature: Smart sensors track exactly how much water your plants need, reacting to changes in temperature and humidity.

Controller decides when to water: WaterMate automatically triggers watering when required, preventing over- or under-hydration.

Split-zone watering for different crop needs: With multi-zone control, you can use different programmes for seedlings or mature plants, all within the same irrigation system polytunnel setup.

Automatic watering which stops when done: Once ideal levels are reached, watering shuts off, saving time and energy and preventing wastage.

Solar-ready for allotments and remote sites: No mains power? WaterMate’s solar-compatible model keeps your irrigation for polytunnels running efficiently off-grid.

Compatible with water butts and tanks: Integrate seamlessly with tanks or water butts for a polytunnel watering system that’s perfect for eco-friendly or low-infrastructure gardens.

Buy WaterMate Mini

How Smart Irrigation Improves Polytunnel Results

Consistent watering for stronger root growth

Smart sensors ensure your soil stays evenly moist, encouraging healthy, deep root systems.

Less risk of over- or underwatering

Automated control prevents the extremes that lead to wilting, rot, or stunted growth, which are common problems with manual watering.

Saves hours weekly in summer

No more standing with a hose. Your irrigation system for polytunnel works automatically, freeing up time for harvesting or rest.

Reduces stress during heatwaves or holidays

Whether you’re away for a weekend or managing multiple tunnels, our system keeps your crops perfectly hydrated without supervision.

Uniform watering means fewer plant diseases

Even moisture levels help prevent issues like blossom end rot and leaf mould, especially in sensitive crops like tomatoes and peppers. 

Early morning watering preserves soil moisture

Automated scheduling means watering happens when evaporation is lowest, helping your drip irrigation system for polytunnel work efficiently.

Improved seedling propagation and flowering

Stable conditions support healthier transplants and more reliable flowering and fruiting phases.

Confidence to scale up growing

With an automatic watering system doing the heavy lifting, growers can easily expand their beds or add zones without increasing workload.

What Sets Our Watermate Range Apart?

  • Automated sensor-based irrigation system

  • Genuinely ‘smart’, responding to live conditions

  • Works off-grid - no mains power required

  • The only ‘everything you need in one box’ complete kit

  • Responds to temperature changes, adjusting watering frequency on hot or cool days

  • Uses industry-standard irrigation fittings

  • Most customisable and powerful (WaterMate Pro), irrigation system available 

  • The only system designed and Made in Britain
Buy Your Automatic Irrigation System

Off-Grid and Solar Power Use in Polytunnels

According to Allotment Insights UK (2023), more than 50% of UK polytunnel growers are off-grid, making solar compatibility a must-have feature.

With WaterMate, a compact 10W solar panel charges an onboard battery, giving the controller enough power to water for 10 minutes / day during an averagely sunny day in the UK, which equates to 120 litres. Additional solar panels can be added for shady locations, or connected to mains power where available.

Our solar setup ensures your irrigation schedule runs like clockwork, even when you’re completely off-grid.

That means your plants stay hydrated through cloudy spells and weekends away, with no manual intervention needed.

Benefits of a Solar-Powered Irrigation System

  • Provides off-grid autonomy
  • Fully automatic, even during cloudy weeks
  • Doesn't need power or mains water supply

Which Polytunnel Growers Use WaterMate?

From weekend allotmenteers to eco-conscious veg growers, WaterMate supports a wide range of polytunnel setups. Whether you’re growing a few trays of seedlings or managing a thriving veg tunnel, WaterMate is designed to adapt to your space, power source, and growing goals. Its features make it ideal for both beginners and experienced growers looking to simplify irrigation without compromising results.

Allotment growers with polytunnels

Keep crops evenly hydrated through heatwaves and changing weather, with no more daily watering runs.

Home veg growers using water butts

Perfect for smaller tunnels or raised beds powered by rainwater collection systems.

Off-grid gardeners using solar

Pair your automatic watering system for polytunnels with solar power for full independence from mains electricity.

Growers starting plants from seed

Gentle, consistent watering supports strong germination and reduces seedling losses.

WaterMate Models & Kit Options For Every Tunnel Size

  • WaterMate Mini

    Dual zone | Up to 6 m²

    Ideal for small polytunnels, cold frames or raised beds. The Mini bundle ships as a dual-zone kit (≈3 m² per zone), supports up to 40 drippers, and includes solar or mains power options, which are perfect for salad leaves, herbs and seed trays.

    Buy WaterMate Mini 

  • WaterMate Pro

    Expandable Multi-Zone | Up to 6 zones

    Built for larger or mixed-crop tunnels. The Pro can be expanded with extra zone kits to support up to six separate watering zones (20m2 per zone), giving independent control for tomatoes, peppers, herbs and more. It’s the most powerful and customisable automatic watering system for polytunnels, designed for serious growers who need flexibility and coverage.

Product specifications and features are subject to ongoing improvement. For the latest details, please see individual product listings.

FAQs

What crops is WaterMate good for?

Anything that needs watering! WaterMate works brilliantly for a wide range of polytunnel crops, from salad leaves, tomatoes, and herbs to strawberries and peppers. You can set up watering zones to match different plant types, so each crop gets the right amount of moisture.

Can I use a water butt?

Yes. WaterMate can draw from a water butt, making it perfect for eco-friendly growers. Many users save 20-50% more precious rainwater compared to hand watering, as the system delivers water directly to the roots with minimal waste.

Is it hard to install?

Not at all. Each kit includes clear, step-by-step instructions, all tools required and most users have their system up and running in a morning or afternoon. The pipework is flexible and a top tip is to put the ends into hot water for easy connection to various fittings.

What if I don’t have WiFi in my tunnel?

No problem. WaterMate operates automatically based on the schedule you set, even without WiFi or constant connectivity. You only need WiFi if you want to adjust settings remotely through the Harvst web app.

What are the best times of day to irrigate in a UK polytunnel?

Early morning is ideal, followed by evening to reduce evaporation and ensure efficient water use. WaterMate’s timer makes it easy to automate these times so your plants always get a consistent, weather-smart watering routine, even through the cooler UK months.

Can it handle winters?

Yes, although the control unit should be covered. Part of the manufacturing process is ensuring that Harvst’s solutions are designed to handle changing climates.

Automate Your Polytunnel Watering with WaterMate

Whether you’re tending a small home tunnel or managing a full allotment setup, WaterMate makes it easy to keep your plants thriving automatically. With tunnel-ready kits, solar-powered options, and precision watering control, you’ll save hours each week while using up to 50% less water.

Join hundreds of UK polytunnel growers who already use WaterMate to grow more, waste less, and enjoy hassle-free harvests all season long.

Find your WaterMate polytunnel drip irrigation kit now!