How to Set Up Ventilation in Indoor Grow Room
Every indoor grow room needs ventilation in order to function properly. But there are many questions before installing one: How to calculate the correct exhaust fan capacity? What to look out for when bringing fresh air into the grow room? In what direction to point circulation fans? All answers and more can be found in the following article.
Be it a grow room or grow tent, enclosed environment requires constant exchange of air. Plants consume carbon dioxide (CO2) and release moisture in the form of water vapour. If you do not suck out the "used" air full of moisture, your plants would not thrive and would be at risk of developing mould, which loves wet environment. Simply put – if you are serious about growing plants under artificial light in an enclosed space, well-functioning ventilation is paramount to success.
The exhaust fan takes the hot, stale air out of the grow room, along with any smell. That is why it is often recommended to attach a carbon filter to it, which reliably captures the aroma of certain plants. They come in various sizes and the best is to pick the ones with slightly higher recommended airflow than the maximum output of your fan.
When choosing an exhaust fan, our primary parameter is the size of the growing space. A helpful guide is the fact that all the air in the grow room should be changed approximately every minute, i.e. 60 times per hour. Multiplying the volume of the room by 60 will give you the approximate number of cubic metres of air that must be extracted per hour. For example, a growing tent measuring 1.2 x 1.2 x 2.0 m has a volume of 2.88 m³. This means we have to take out 172.8 m³ (2.88 x 60) of air per hour. If we calculate with certain loss of power after the installation of the filter, we will find out that a Prima Klima PK100 fan with an output of 280 m³/h is perfectly sufficient.
Our tip: Modern EC fans are much quieter and more cost-effective than older types with brush motors.
For some settings, it is necessary to extract air from the grow room over longer distances. Various types of ventilation ducts are used for this purpose. For shorter and simpler ducts, one can use Aluflex aluminium ducting. Another ducting Combiflex is also equipped with a laminate layer that increases its compactness. If one wants to reduce noise as much as possible, the Sonoflex duct with its noise insulation layer is an ideal choice.
Our tip: Secure the joints between the ducts and the fans with metal strapping.
The vast majority of grow tents is equipped with openings at the bottom to let fresh air in. Ventilation holes can also be found in the upper parts of your grow box. They serve to connect the exhaust fan. And since the warm air moves upwards, the exhaust is most effective at the top of your tent.
There are growers who also use fans for the supply air. Thanks to this, they have more control over the climate in the growing room. Supply fans are mainly used in larger operations where a passive supply might not be sufficient. Be it a small grow box or a massive indoor grow room, the amount of air brought in should always be slightly less than the volume taken out. This way one can create a slightly negative pressure so that all the air passes through the filter first and no smell leaves the grow room.
In nature, plants are constantly exposed to gusts of wind. This way they are naturally stimulated to harden their stems. The wind also helps establish a suitable microclimate between the leaves, discouraging pests and preventing the development of mould. In enclosed grow rooms, the wind needs to be replaced with various types of fans. They should never blow directly onto the plants, instead it is best to point them in the space between the plants’ tops and the light.
We can also recommend buying clip fans to save space in your grow tent. A popular choice for medium sized grow boxes with a growing space of 1 to 2 m² is the Monkey Fan two-speed clip fan. Circulation fans are suitable for larger tents and grow rooms.
Still not sure about what equipment to buy? Do not hesitate to consult our customer service!