Ventilation - Why is it so important?
THE MORE YOU KNOW - THE BETTER YOU GROW
Keeping your cool: Growroom ventilation tips and tricks
Ventilation is as important as water, light, heat and nutrients (Cervantes, 2015). If we understand
the basic requirements of our chosen crop it’s actually quite a simple and affordable process to
optimise the environment. We need to recognize the required hardware capabilities and the
desired environmental parameters to select the appropriate ventilation and environmental
control equipment.
The most important factor for hobby indoor or small domestic gardeners is selecting the
appropriate fan(s) and ventilation points to control airflow and temperature. Fans are
predominantly used to control growroom climate by extracting the stale warmer air and by
providing your plants with a source of fresh, cool air.
Calculating the ideal fan size for small growrooms in the Australian climate generally states that
we require a complete exchange of the air in the room every 60-120 seconds (Palmer, 2015).
This provides enough air movement to remove most of the heat from HID lighting and prevent
stagnant pockets of stale air forming.
When stale air occurs, stratification around the leaves is likely to slow growth and cause
problems with mould and rot. The internal air must be moved via the use of natural currents or
mechanically to imitate outdoor climates and environmental conditions. Quest F9 Air Movers
and our new range of CoolSox are a seriously efficient means of moving air in any size cultivation
facility!
Calculating the fan size for a small growroom is a fairly basic formula. It’s important to remember
that we should balance the air intake and extraction to create atmospheric negative pressure
(this helps control pests and unwanted odours).
It’s important to use a larger exhaust fan than intake and the generally accepted ratio is 1:4
(Cervantes 2015). This ensures that all extracted air passes through a carbon filter for the removal
of pathogens and undesirable odours. This can put some pressure on the grow tent stitching
and wall lining. If the intake fan is more powerful than the exhaust, your growroom will balloon
and leak odour. Most common indoor grow tents have lower mesh vents that lightly filter the
inward airflow and these importantly reduce the strain on the tent if an appropriate intake fan is
not used.
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