A ventilation system is essential for greenhouse production. You need to evacuate heat from your structure while making sure fresh air can come in. Choosing the right ventilation system helps ensure healthy and productive crops.
How to find the right type of ventilation for your needs
There are two kinds of ventilation. The choice depends on your budget, the model of your greenhouse and the requirements of your crops.
The only source of natural ventilation is the wind outside. The exchange of air is achieved with side and roof openings. This type of ventilation is comparable to air coming in and out of a window in your home (although this is unstable and unpredictable).
In general, natural ventilation is sufficient to make sure your greenhouse runs efficiently. The side doors take care of lower ventilation, with warm air rising while the chimney of effect of the sunroof pushes it outside. Fresh air from the outside penetrates through the roof and quietly descends to gently cool the greenhouse. The combination of these two openings is sufficient enough that you don’t need mechanical ventilation. The positioning of the greenhouse is a key factor in optimizing natural ventilation.
There are two key principles of mechanical ventilation: extraction and positive pressure. For extraction ventilation, a fan pushes the air to the outside, while the outside air enters via shutters installed on the greenhouse. Positive pressure ventilation draws fresh air from outside to inside the greenhouse.
Positive ventilation is generally more economical for an individual greenhouse such as OvaltechTM , and offers the same results as extraction ventilation. It isn’t recommended for multi-chapel greenhouses, which require a highly developed and more expensive ventilation system. For these types of greenhouse, we recommend an extraction system.
Mechanical ventilation is essential for year-round productions, as well as for greenhouses that are less exposed to wind.
Proper ventilation at the start and end of the season
In spring, you should avoid venting with side openings, as cold temperatures can have a negative impact on young shoots. It’s best to opt for ventilation from the top of the greenhouse with a roof opening. This strategy also applies to the end of the season.
The choice of a ventilation system adapted to your greenhouse and production needs ensures healthy and productive crops. The experts at Harnois Greenhouses can help you choose the equipment that’s best for your needs and guide you on how to use it.