Background information
My new cannabis grow setup is an expensive dream
by Martin Jud
How I stopped the neighbours from smelling my weed and how much that cost
6.1.2024
Translation: Patrik Stainbrook
Cannabis flowers have a light fruity-sweet scent. However, a tent full of flowers will be pungent. To keep my apartment and the stairwell I share with my neighbours fresh, I use a duct fan and an activated carbon filter.
When the farmer next to your house fertilises his field, it stinks. The problem isn’t only the disgusting smell itself, but also its intensity. At least on this second point, manure and the smell in my new cannabis tent will produce are no different. After all, the terpenes produced in the resin glands of the hemp plant are so pungent that a single flowering cannabis bud is enough to incur the wrath of my neighbours.
An exhaust air system with activated carbon filters can prevent unpleasant odours. In this article, I’ll explain how big it should be and how powerful a tube fan you should get. I bought «oversized» products for my small tent and go against the norm by using them outside the grow box.
This is the last post in my miniseries. As a bonus, you’ll find out at the end of this article how many watts the individual components of my growth setup draw and how high the electricity costs are over 110 days of plant cultivation were. You can find the previous three articles here:
Why you need an exhaust air system and how it’s constructed
There are two reasons for installing an exhaust air system:
- It provides sufficient fresh air for your plants.
- The activated carbon filter removes all odours from the air in the tent. Just like a steam extractor with an activated carbon filter in a kitchen.
Typically, you install an exhaust air system at the top of the grow box in the following order: Active carbon filter > Ventilation hose > Pipe fan > Ventilation hose to the outside.
If the components are located outside the tent, you’ll have more space for tall plants. Here, the order of components is reversed: Pre-filter box in the tent > Ventilation hose to the outside > Tube fan > Ventilation hose > Activated carbon filter.
With a system inside the tent, a felt cover on the activated carbon filter removes dust out of the air. If the tube fan and the rest are outside, they suck air into the hose unfiltered. Unless you use an additional pre-filter box, as I do, in the back left corner of the tent.
If you’re wondering whether extracting air from the bottom of the tent causes heat to build up at the top: yes. But only if you don’t do anything about it. In my article on successful indoor cannabis growth, you can find out how to tackle this.
How powerful the tube fan should be and the right size for your activated carbon filter
To provide the plants with sufficient fresh air and keep the temperature and humidity low, you need a suitably powerful tube fan and the appropriate activated carbon filter. You should also ventilate the room in which your grow box is located well. In addition to a tiltable window, or even better a skylight in the same room, a door can also help with regulation.
To choose the right fan, you need to know how much air it should move over what period of time – i.e. how many cubic metres per hour (m³/h). As a rule of thumb, all air in the grow box should be exchanged after five minutes at the latest during the vegetation phase. During the flowering phase, this should go down to two minutes max.
Why I use «oversized» components
In the end, I bought even stronger components. The reason? I want a setup that’s as quiet as possible and hopefully lasts a long time. The following factors make a quieter tent:
- The diameter of the ventilation hose – the larger, the quieter.
- The length of the ventilation hose – the shorter, the quieter. It’s one of the reasons why I extract air from the bottom of the tent and not from the top.
- The design of the tube fan.
After hours of research, I chose a quiet model for the raw fan but it wasalso oversized. Still, the TD-500 Silent (150-160 mm) tube fan from Soler&Palau costs CHF 315 and, at 580 m³/h, goes above and beyond the 336 m³/h target:
At full blast, I could even use it on the set of a hairspray commercial. Or as bellows for a fire. In my case, a step transformer throttles it down.
For the activated carbon filter, I actually wanted to go for this Rhino Pro filter, but it wasn’t available at the time. The Phresh activated carbon filter chosen as a replacement hasn’t disappointed me so far:
I don’t see the fact that it’s designed for 600 m³ per hour as a disadvantage. It should actually last longer as a result. I hope to achieve around eight grow cycles with the Phresh P600. If that works out, I wouldn’t have to buy a new one for another eight years.
Nevertheless, a powerful fan and activated carbon filter somehow work better with the equally «oversized» LED lamp. What’s more, the exhaust air components account for less than a third of the total cost of the setup, which is CHF 2627.40. I’m more than satisfied as a result.
Wasn’t there something else? Power consumption?
The following list shows how many kilowatt hours of electricity I need for my current grow cycle based on my measurement results:
I hope you enjoyed my short series on cannabis. Goodbye for now, at least until I’ve got more to report. With my PAX vapouriser in hand and fragrant flowers at my side, I’ll now return to less controversial topics from the tech sector.
Header image: Martin Jud
Martin Jud
Senior Editor
martin.jud@digitecgalaxus.chI find my muse in everything. When I don’t, I draw inspiration from daydreaming. After all, if you dream, you don’t sleep through life.
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