Last updated: May 4, 2020
Growing in an enclosed environment like a grow tent can get downright sweltering.
Cannabis plants perspire all but about 3% of the moisture they collect, combine that with a light rigging and you’re looking at a literal sauna in a box.
So, what can be done to combat a hot grow tent? Well, there are quite a few techniques to try out:
Starting with a very obvious option, but taking note of it since some growers may not be aware of how effective a small AC unit can be inside of a grow tent.
Just a small portable unit is needed to bring down the temperature in a small area. Make sure it’s running consistently, though, since an AC unit tripping on and off all day can really raise the power bill.
Be sure that the fan connected to the exhaust is handling the size of the grow tent appropriately and that it is running at peak efficiency.
A fan that is too small, or just isn’t functioning enough, will cause air to stagnate fairly quickly and cause temperature fluctuations. Intake fans should be checked as well because they generally have an easier time with things than exhaust fans.
If the temperature in a grow room is consistently too high, despite best efforts to assuage the issue, then the lighting system that’s in it probably is too hot for the tent. There are a few different options in cooler lights to choose from, so it’s not a lost cause by any means.
LED lighting systems are just now getting popular use after decades of trying to get into the market. The current tech is finally up to par with things like HID lamps as far as the lumens they produce and, the best part is, they run quite a bit cooler.
LEDs are a great choice for a grow tent for this reason alone and should be considered in scenarios like this.
These work by extracting heat, via either water or air, off of the light rig via either a pump or fan.
Air-cooled rigs are somewhat effective as long as ventilation is already pretty strong in the room, but is only marginally useful in a space that’s already overheating consistently. They work by constantly blowing air across the surface of the light by way of a fan installed in its reflector, moving heat along the way.
Water-cooled rigs work very well, though they tend to cost quite a bit more than the other options.
These work by using a circulator pump that pushes cold water through ducting around the lights. The heat dissipates into the water, then moves along into a chiller, before back up and around again. If the option is available, water-cooled rigs are an amazing way to keep a grow tent cool.
We mostly recommend this as a kind of stop-gap in between finding a better solution, as this requires constant replenishment of ice throughout the grow if used as the main source of cooling.
The concept is to run an intake line through a cooler that has been modified with holes for ducting to run through. Then simply keep it filled with ice, and now the intake fan is blasting cold air whenever there is ice in the cooler.
This works alright but should be seen as a way to buy time versus a permanent solution.
Insulation helps to trap heat in a tent, true, but this is a non-issue if ventilation is up to par. Instead, insulation should be seen as a way to keep cool air from dissipating.
In conjunction with an air-conditioner or other cooling apparatus and good airflow, proper insulation is one of the best ways to maintain a consistent and cool temperature for plants.
This is of major importance for tents that are exposed to weather variables, such as when placed outside or in a non-insulated part of a house like an attic.
Of course, this is not a complete list of the many different ways people have found to cool a grow tent off, but it should give a good idea of simple cooling ideas any grower can accomplish.
Remember that cannabis plants love a constant temperature more than an ideal one. Sometimes it is better to have a grow tent is a few degrees warmer consistently than to have it swing up and down around that ideal temperature.
Featured image credit: Wikimedia
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