Marijuana Grow Room Odor Control Guide

grow room odor control

Being an indoor cannabis grower is fun, exciting, and rewarding. However, the distinct marijuana smell in your house can linger in the air, causing you possible troubles when it comes to the privacy of your growing space.

Nevertheless, marijuana plants need fresh air in order to grow healthy and strong. That’s why we have compiled digestible marijuana grow room odor control guide to help you with your cannabis growing journey.

For a start, let’s check out why ventilation is crucially important for the well-being of your green ladies.

Why Marijuana Grow Rooms Need Reliable Air Circulation?

Picture yourself in a room where the air is stagnant to such an extent that it gets hard to breathe easily. You’ll most probably open the windows and let the fresh air enter freely. That’s a pretty quick fix, right?

However, your marijuana plants can’t possibly self-fix issues due to poor ventilation like we, humans, can.

When growing cannabis outdoors, wind circulates naturally. As a result, the constant flow of fresh air helps cannabis plants to give off water vapor through their leaves. What’s more, the gentle breeze helps to strengthen the stems.

With indoor marijuana growing, the consistent flow of fresh air is even more crucial than with outdoor growing operations.

The reliable air circulation in your grow room helps to keep tiny crawlers at bay. That’s because fungi, bugs, and mold adore hot and humid environment where the airflow is poor and/or inconsistent.

If you underestimate the importance of proper ventilation in your grow room, you’re bound to encounter multiple possible problems throughout your cannabis growing operation.

Meanwhile, the pungent smell of marijuana can quickly spread throughout your house, putting your growing mission straight on the public radar.

Just several years ago learning the best practices in marijuana grow rooms odor control required tons of research through scarce pieces of information.

But nowadays, things have dramatically changed, and it is easier than ever to understand how to provide reliable air circulation in your indoor grow room based on your unique needs.

Indoor Marijuana Growing Odor Control Guide

For a start, the best ventilation setup in your growing space will depend on several important factors.

Below, we will break down all the bits of information you want to know in an easy-to-digest way.

Humidity and Temperature Levels in your Grow Room

You can’t possibly control the odor in your marijuana grow room without controlling the temperature, as well as the humidity levels.
Humidity – Marijuana Growing Humidity Moisture – Growing Weed

Generally, marijuana plants in vegetation thrive in humidity levels ranging from 40%-70%. Starting from 70% humidity, you need to gradually lower this rate with 5% weekly until you reach 40% at the start of flowering. The temperatures should be kept at 20-28 degrees Celsius (66-70 degrees Fahrenheit) with the lights ON and not more than 4-5 degrees lower with lights OFF.

When your green ladies begin blooming, temperatures should be kept at approximately 20-26 degrees Celsius (66-68 Fahrenheit). It is crucial to keep humidity levels at about 40%-50%. Anything above 55% is considered bad news for most marijuana strains.

But do keep in mind that different marijuana strains have a slightly different tolerance to humidity and temperature rates. That’s why it’s super important to pick your seeds from reputable retailers who are able to provide quality descriptions of each strain’s specifications.

During vegetation, temperature and humidity rates won’t be that much of an issue in terms of odor control.

As soon as flowering begins, high humidity and/or temperature will further enhance the distinct, pungent smell of marijuana indoors.

It is during flowering that cannabis plants start producing more and more trichomes. A clear view of the trichomes is invisible to the naked eye but they are all over the glandular “hairs” of marijuana plants – the parts known as pistils that start growing in number as flowering develops over time.

It is thanks to the increased production of trichomes that the notoriously aromatic molecules – the terpenes start to penetrate the air. The more trichomes develop, the more of odor envelopes the entire grow space because trichomes are like tiny molecules factories.

But can’t you simply use an air conditioner along with dehumidifiers to control the odor in your grow room?

Air conditioners and dehumidifiers may certainly be helpful; however, that’s only to some extent. The type of ventilation that will ensure best results need to move both heat and humidity outside of the room, and that’s not air conditioners’ and dehumidifiers’ specialty.

And so we logically get down to the rest of the factors that affect the quality of odor control in your indoor marijuana garden.

We’ve compiled these factors in the form of questions. This way, it will be easier to develop a deeper and better understanding of picking ventilation setups and methods that will work fantastic for you.

How many cannabis plants are being grown

If you’re planning to grow only a handful of plants, ventilating the grow room can be quite a painless task.

The truth is, it can literally cost you nothing in the case the growing space can be regularly ventilated by opening a nearby window several times a day.

Combine this tried-and-tested, on-a-dime method with a simple oscillating fan and a dehumidifier to keep excess humidity at bay and you can establish a proper air circulation without any serious investments.
Video by Urban Burner – How to control grow room humidity levels

However, this method is not the most efficient option when it comes to fully eliminate marijuana odor. That’s where odor neutralizers can come very handy.

Nevertheless, not all marijuana growers have enough free time to open the windows every several hours so if you’re one of the busy bees working 8+ hours a day, you’d better go for a reliable ventilation system.

Smell of Marijuana and Carbon Filters

As a rule of thumb, if you want to eliminate excessive cannabis smell from your grow room fully, a carbon filter is what you need. Carbon filters can destroy approximately 90% of marijuana odor.

If limiting marijuana smell within about 50% works fine for you, then fans will work great, and you don’t really have to go for carbon filters.

Also, don’t forget that choosing the right strain is crucial. If odor control is of utmost importance to you, go for strains that are known to release less of a skunky smell than other cannabis varieties.

The Type of Grow Light Being Used

LED grow lights setups produce very little excess heat.

The same goes to low power 250W HID lighting systems, as well as CFL grow lights setups which are well-suited to small-scale indoor cannabis growing operations.

On the contrary, if you’re growing with HIDs or ceramic metal halides, poor ventilation can literally fry your marijuana plants.

Where Cannabis is Being Grown is a Factor

Modern-day grow tents come with ventilation systems that are already built-in.

Grow tent manufacturers know how to calculate the size of the filters and/or fans needed to suck away all the stagnant air based on the size of the tent. This means you don’t have to worry about setting the ventilation system on your own. Simply put together the tent kit and get down to growing.
Video by Growers House – Best Indoor Grow Tent Kits – How To Setup Your Indoor Home Garden

On the other hand, those who are growing in a small cabinet, a wardrobe or any other grow space of similar size, can opt for the old but gold manual method of ventilating the air mentioned above (just open the windows several times a day).
Similarly to modern-day grow tents, if you opt for an advanced grow cabinet, ventilation will be already set up for you.

What’s more, high-quality grow cabinets also come with built-in grow lights, and some even feature separate chambers for vegetation, cloning, and flowering.

Locking systems of top-grade grow cabinets allow you to keep your indoor marijuana garden strictly private while also immediately blocking any excess cannabis odor once locked.

Now, let’s get down to the practical side of understanding, choosing, and assembling the ventilation setup in your grow room.

Whether it comes to the good old standing fans or oscillating fans, you can’t go wrong with utilizing their power to help you ventilate the grow room. Fans ensure that air circulates well, and they are very useful when it comes to keeping odor and temperature on the low side.

Also, fans are easy to find, effortless to install, and are quite affordable. So far, so good.

But fans can’t possibly eliminate marijuana odor completely, and they are not the most reliable devices for controlling humidity levels in a bigger indoor grow space.

You can increase the odor control power of traditional fans by combining them with ducted intake and exhaust fans.

Grow Room Intake and Exhaust Fans

As a rule of thumb, during vegetation, air needs to move through the grow room every few minutes. During flowering, it needs to move every minute.

Here’s where a simple calculation taking into consideration the CFM rating of fans comes handy. You need to measure the cubic feet/meter of your grow space.

For this purpose, measure the width, the length, and the height of your grow room. Let’s say the length is 4, the height is 5 and the width is 6.

Now, multiply these numbers and you’ll get the average CFM that will be enough to ventilate the grow room. 4x5x6 = 120, so 120 is the average CFM of the fan we’re looking for based on the example above.

Exhaust fans and intake fans can be mounted by ducting. However, you may also need to use chains or cables, depending on the way you choose to position the extractor fan.
Video by growing4cure – VENTILATION for CHEAP Budget Marijuana grow tent Ep.4

Also, you may need to use clamps and reducers but that’s in the case ducting is not the matching size of the grow room.

Finally, you’ll have to connect outside ducting to a fan or a window so that the hot, stagnant air can flow away from the grow room. Attaching a carbon filter to your extractor fan is the most reliable method for fully controlling odor emissions.

With grow tents, it’s easy to spot whether intake fans are functioning correctly because you will notice the walls of the grow tent being sucked inward as the ventilation is set and running.

Back to Carbon Filters and Cannabis

Activated carbon filters, also known as carbon scrubbers work by utilizing highly ionized, activated carbon. This unique type of ventilation literally “scrubs” away all the fine molecules present in the air.

As a result, the tiny particles that otherwise linger in your marijuana grow room are trapped inside the filter’s main cylinder.

Most noteworthy, carbon filters are superior because they also suck away any traces of mold spores, hairs, and dust to ensure your cannabis plants grow healthy through minimizing the risk of possible contamination.

In order to choose the right carbon filter for your grow room, use the same CFM calculation as with intake and exhaust fans.
Video by Everest Fernandez – Grow Room Ventilation 101

Measure the width, length, and height of the grow room and multiply the numbers to get the average CFM that will work best for your indoor garden. For instance, 4x4x4 grow room will need a carbon filter featuring at least 64 CFM.

Make sure to choose an inline fan that matches the CFM of the carbon filter you use, as well as its size. For example, if you go for an 8-inch carbon filter with a 780 CFM max, you need an 8-inch inline fan with a 780 CFM max, too.

There are numerous carbon filters available to suit each budget. But do keep in mind that high-quality carbon filters that seem pricey at first can prove to be a wiser investment in the long run as they use better quality parts, resulting in increased durability.

When it comes to inline fans, top-grade products function very discreetly in terms of noise levels whole lower-end products are typically much noisier.

There are two major ways of using a carbon filter in combination with an inline fan.
Video by Everest Fernandez – How do I hang a carbon filter on my own?

The first way is to use the inline fan as an intake filter by having the air blown directly into the filter. The second way is to use the inline fan as an exhaust filter by getting the air sucked through the carbon filter.

If your marijuana grow room doesn’t exceed 3×3 in size, an inexpensive homemade carbon filter can work perfectly fine, too.

A DIY carbon filter can provide efficient air circulation for small tents, cabinets, and micro-grows in general so do not overestimate its functionality.

Also, a DIY carbon filter can be a cheaper alternative only in the case you have some of the materials for your project already available so it’s really a very personal matter of choice.

Marijuana Odor Neutralizers

Last but not least, odor neutralizers can do some pretty decent job in controlling the odor in your marijuana grow room.

Do keep in mind that odor neutralizers have little to do with air fresheners. Instead, odor absorbing gels are what you need to help you get rid of the odor in your grow room.

Of course, odor neutralizers can’t possibly ensure that your plants will get a consistent flow of fresh air to help balance temperature and humidity along with recycling the already used CO2 in your grow space.

But when the final stages of a flowering kick in, even a well-functioning ventilation setup may fail to eliminate all the traces of that pungent, delicious, lingering cannabis smell in your house.

Odor neutralizer work by catching the aromatic molecules released by cannabis plants and replacing them with other scents that are designed to be appealing enough to conceal any other scents in the room.

But then again, odor neutralizers are only an additional odor-minimizing option, and not your main source of removing away marijuana smell.

Marijuana Grow Room Odor Control Guide: Key Takeaways

Since growing cannabis is a continual process of learning, don’t get discouraged if you are faced with difficulties while trying to set up perfectly well-controlled marijuana grow room.

Taking the time to watch how the different growers are managing odor control together with humidity and temperature levels can be very helpful but you can’t possibly blindly follow anyone else’s growing experience.

Don’t rush and don’t panic, your marijuana plants will pretty much “tell” you when something’s right or wrong but you need to learn to drive your own conclusions and do your research rather than looking for some fit-them-all magical formulas that work wonders.

If you take into consideration all the facts and tips we’ve shared in this marijuana grow room odor control guide and add a healthy dose of patience and care, you’re bound to enjoy happy and successful cannabis growing. Or at least that’s what we hope for.

You can help us spread the knowledge and love for cannabis cultivation, too. Join us with any questions, tips, comments, or thoughts and let’s make this world a greener, better place together.

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