Fans are a standard equipment for professional greenhouses, and are becoming more popular with hobby tunnels. The cost of such a device compared to the benefits offered makes it a profitable investment. Greenhouses are used to extend the growing season. The foil stretched on the frame contributes to a favorable temperature for the development of plants under cover.
Thanks to lateral ventilation, adequate humidity levels are maintained inside the structure. Using the adapted cover and accessories optimizes the growing process, while additional support systems improve crop quality. In places where sudden weather changes occur, as well as considerable temperature fluctuations, regular ventilation may not fulfill its role. With the help of fans, it become much easier to obtain the microclimate required by plants.
Air circulation under cover
An air flow is very important with cultivation under cover , and limits the development of pathogens. When conditions change outside, it has an influence on the microclimate inside the tunnel. Temperature changes between day and night are a great example. On sunny days, the greenhouse heats up and that heat remains for longer as it is “stored” under the foil. In the evening, with lower temperatures, the accumulated heat slowly fades inside. Plants lose less energy to fight the cold, focusing on development.
Moisture in a foil tunnel
High and low temperature have an impact on humidity level inside the structure. With watering, plant growth, precipitations, sunny and cloudy days, frosts etc, humidity levels are bound to vary. A persistent high humidity is ideal for the development of diseases and create good conditions for pests. On the other hand, a lack of it causes the plants to dry up and eventually die. Ventilating a foil tunnel is not difficult, there are several conventional as well as automatic solutions.
Ventilation in a garden tunnel
The easiest way to ventilate the foil tunnel is to open the door. With small constructions, it is more than enough. The effectiveness of this method decreases as the size of the greenhouse increases. The bigger it is, the smaller the air flow. Often, customers upgrade their construction with an extra door to create a flow from both sides of the tunnel. Unfortunately, with a very hot summer, it may not be enough.
Here, side and roof ventilation will come to the rescue. The first one is activated on both walls of the tunnel, while the roof system consist of top openings. Lifted and lowered with cranks, they provide air flow through the entire length of the greenhouse. In summer, when the sun is at its peak, hot air that accumulates in the tunnel is evacuated and replaced by a cool one. The presented methods are adapted to hobby cultivation or professional greenhouses. In large commercial plantations where control of the environment is essential, vents for the polytunnel will be necessary.
Automation for cultivation under cover
This is not a vision of the future. Automation is not only for large growers, smaller ones can also afford it. Year after year, technology is getting cheaper as new solutions come in, and older ones become less expensive. Fans connected to temperature sensors inside and outside operate as soon as conditions programmed by the grower are achieved. That way, it does not have to be permanently on, and users can focus on matters that require attention. For those who want to have everything under control, there are also applications installed on mobile devices that regularly report changes and system activities. A fan for a foil tunnel is one of the solutions available. Growers often implement irrigation systems, shading, heating, and by combining them into one system, they manage to run a year-round cultivation under cover.
Our professional foil tunnels are made of steel pipes and profiles, protected from corrosion during production. A zinc layer was applied by galvanization or hot dip galvanization . Additionally, the frame can be reinforced with brackets, stabilized with anchors and supported by a truss. Such a design is a guarantee to resist difficult weather conditions. Modularity is an advantage of Krosagro structures. By purchasing such a facility, users have the possibility to modify it over time, extending in length or width. Before ordering the structure, please provide the manufacturer with information about potential accessories that will be mounted. The frame will therefore be prepared for such modifications.
Type and location of the fan
The kind of fan to choose will depend on the cultivation method and the size of the greenhouse. Even before purchase, it is necessary to check its efficiency, how many are needed for a proper ventilation. In greenhouses that are more than 30m long, air movement is limited in the middle of the structure. For this purpose, fans are installed. Fixed on the construction, they enable extraction of inside heat and allow fresh air in, for an effective process. They can appear alone or as one module. How and where they will be located will depend on the required performance. However, it should be checked whether the structure is able to withstand such loads.