Grow room ventilation is important! A grow room with stagnant air is a grow room in disarray. When it comes to indoor gardening, most of the focus gets thrown on the lights, the nutrients, and grow media because these factors are vital to a fantastic and huge harvest, but without proper air circulation, you won’t even make it to harvest in the first place.
Without air circulation you should expect:
- Dangerously high temperatures that stunt growth and kills plants
- High humidity levels which lead to mold that will ruin your plants
- Weaker stems that are prone to breaking
- Lack of C02 which will suffocate plants
- High odor
It’s recommended that the air in your grow room/tent is exchanged every 1-5 minutes. This will go far in helping keep your CO2, oxygen, temperature, and humidity levels all under control.
When it comes to proper air circulation you want to look at three factors:
- Fresh air being introduced into the grow room
- The amount of air circulation happening in the grow room itself
- Old air being removed from the grow room
Let’s look at these factors by working our way backward – you’ll soon see why this works.
Removing Air From the Grow Space with Inline Fans and Blowers
By setting up our exhaust fan first we can accomplish not one, but three helpful components to growing, which will eliminate a lot of time, cost, and stress from our lives.
An exhaust fan will, of course, remove stagnant air from your grow room, but that downplays what it all it really can do. First, it can help with odor control.
Using an Inline fan to control odor
Inline fans can be connected to a carbon scrubber. This will pull all the air from the grow space through the carbon scrubber first, eliminating at least 90% of the smell if properly set up – don’t worry we’ll show you how below.
Passive Intake – How removing air can introduce new air
Second, when you’re using a small to medium size grow tent, you can create a passive intake system with your inline or exhaust fan. It’s the same principle as sucking air through a straw.
With passive intake, you create a lower pressure in your grow space as oppose to the space outside the room. This creates a vacuum that pulls in new air, which in fact, cools air more efficiently than an intake fan blowing air in and over your plants.
With an inline fan is placed at the top of your grow tent and the passive intake hole at the bottom, we can actually create an all-in-one air circulation system that moves air efficiently throughout your grow tent. This might mean your job is already done, just by purchasing an intake fan.
Air Circulation Inside The Grow Space
While a passive intake system can be enough to adequately introduce and remove air, it might not be enough to actually get your plants moving.
We want our plants to dance
Clip-on fans, wall mount fans, etc. are great because they can be set up to directly move air over and through the plants creating a breeze that will strengthen the stems and keep insects off. Strengthening the stem is important, because us gardeners are constantly trying to find a way to grow bigger fruits, veggies, and flowers – which we are very good at, but you must grow a hardier stem if you don’t want these bigger results breaking the them too soon.
Grow Room Hot Spots
HIDs and LEDs are two of the most popular grow lights, and while they are brilliant for growing some of the best plants around, they are notorious for creating hot spots. A light mover is fantastic for expanding your lighting footprint and removing hot spots, but they might not be in your budget. A small fan blowing air over the plants will go far in removing built-up hot spots.
Not All Fans Are Created Equal
If you look at an inline fan, you’ll come across the term “CFM”. This stands for cubic feet per minute, and this rating tells you how much air a fan can move in one minute.
When purchasing an inline fan, you want the fan’s CFM to closely match your carbon scrubber, as this will create the proper rate of push and pull between the units. Your grow space will determine how powerful that fan needs to be, however.
Remember, we want to remove air every 1-5 minutes. To figure out your air exchange rate, you will first calculate your grow tent’s size by multiplying the tent’s length, width, and height. Let’s say you’re using a 4 x 4 x 8 foot tent, which will give you 128 cubic feet of volume. If you choose a fan with a CFM rating of 128, you should expect air to be completely exchanged in about a minute. The amount of ducting and your carbon scrubber will determine if your fan is actually pulling air at its maximum rate.
Your fan will most likely have something that’s reducing its pull – the carbon scrubber and length and twisting of ducting factor heavily – so it’s recommended to pick a strong enough fan that will remove air in about only a minute or two unaffected. This will give you a nice amount of wiggle room just in case. Read More