Irrigation and Ventilation for your Polytunnel

In an ideal world we would all spend every minute of the day in our polytunnels, trying to get the most out of our crops. However, if this isn’t an option, you need to know that your plants are taken care of when you are not around. This is why a proper irrigation and ventilation system is important.


Different plants will have different requirements in terms of how much water they require, so be sure to keep this in mind when shopping for the correct equipment. There are several different options for irrigation systems that you can choose from depending on what it is you’re aiming to grow.

Overhead sprinklers are a particularly common option for irrigation systems as they are simple to install and can be set up to automatic timers to be used at optimal times throughout the day if needed. The only problem with this system is that if set up throughout the whole polytunnel it spreads the water indiscriminately and so would not be advised if you have a variety of plants with different watering requirements.

Drip line kits are also a favourite amongst growers due to the fact that the water flow can be regulated by burying the hose under a level of soil so that the water is not evaporated, and the roots can absorb the water accordingly. As with the overhead sprinklers, these may also be set up to an automatic timer so as to regulate how much water is sent through the hoses.

When using irrigation kits, it is important to tailor these to the ever-changing weather patterns; during the winter the plants won’t need as much water as they would in the warmer summer months. Whilst an automatic timer is ideal for regulating the day to day waterflow, it is important to be sure the amount of water is suitable for the plants you are growing as well as the time of year. Regular checks are crucial to be sure that the settings are right for your plants.



One of the most important factors to consider when growing produce in polytunnels is ventilation. Proper ventilation for your polytunnel is crucial to getting the most out of your crops. Ventilation is not only important for controlling the temperature levels, but also humidity that can result in mould, fungi and crop diseases. Whilst having the doorways open and closed at different points during the day works perfectly well for smaller polytunnels, it is not ideal for larger commercial structures or for filtering the air that comes into your tunnels.

An air intake louvre allows fresh air into the polytunnel which can then be circulated throughout the structure with a circulation fan. This will keep the greenhouse’s climate regular. This is impossible to do simply using the doors to control the air flow, due to the irregularity of the weather.

Fresh air can turn stale and humid fairly quickly inside a polytunnel which can lead to plant diseases. When this happens ventilation fans and extraction fans are ideal for removing this air, especially in the larger structures. For added ease the extraction fan can be used with an automatic temperature switch and control panel.

In smaller structures, a polytunnel roof vent is ideal for removing excess heat without needing to open the doors. Keeping doors open for ventilation can also allow unwanted pests inside which a proper ventilation system can filter out.

For more information regarding ventilation systems to suit your structures, please feel free to contact our sales team on or give us a call on 01282 873120.