How to Smell Proof Your Grow Room

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Are Grow Tents Smell Proof?

If you’re sitting outside and downwind of your grow tent and getting a bit high from the smell, then you already know the answer to this question–and it’s an emphatic, no. There are a lot of great small grow tents available on the market, perfect for home growers.

And they come with some excellent features. But completely containing the distinctive smell of weed is simply not one of them.

Do Grow Tents Hide Smell?

Are you a first-time grower using a grow tent to raise your precious little ones? If so, you may be forgiven if you think your tent will completely take care of the smell situation.

Maybe you have several plants in there getting healthy and strong during their vegetative stage, and you’re not detecting all that much of a stink.

But don’t be fooled. As a rule, weed plants don’t emit that potent of a smell in the early stages of growth, but once they start to flower–look out!

That’s because of the presence of terpenes which begin developing in the trichomes of the flowers at that time. And the more plants you have packed in your grow tent, the more powerful that smell will be.

The zippered door along with the walls and roof of your grow tent will contain some of the smell, but that lightweight construction can only do so much. In addition, plants require aeration as well as humidity and temperature control so your grow tent will have a certain number of ready-made air holes for fans and other ventilation equipment to do their magic.

A grow tent simply can’t and won’t completely hide the smell of your pot plants.

How Do I Control The Smell In My Grow Room And/Or Grow Tent?

That’s the keyword: control. If you’re going to grow weed, you have to accept the fact that you’ll be dealing with a certain amount of that telltale dank smell.

How bad your crop smells will depend on the strain you are growing and the number of plants you have. But, rest assured, you’ll be dealing with it.

Fortunately, there are a few things you can do to tamp the smell down.

1. Get Smell Absorbing Gel

Smell absorbing gels and sprays do a fairly good job of neutralizing odors. One of the most popular products on the market is “Ona Gel” which can be purchased in quart, gallon, and multi-gallon containers.

The product is available in either a fresh linen scent or a fragrance-free option. To use it, you simply place the container in an area where there are smells and remove the lid.

This product, however, should not be left in the grow tent but directly outside where smells are escaping. If placed in too close proximity to weed plants, these odor neutralizers can alter your weed’s aroma and flavor.

Sprays should also not be used directly near the plants as the fragrance in them can end up coating your buds and permanently altering their flavor.

2. Get A Good Carbon Filter

An even better way to reduce the weed smell in a grow tent is by combining a good carbon filter with an inline fan.

Activated carbon has long been used in water purification and air filtering processes as it absorbs, contains, and neutralizes contaminants including odors. By combining such a filter with a powerful inline fan, the fan can pull in large amounts of that stinky air and neutralize much of the odor.

We explain how you control the smell in your grow room and your your tent

“Marijuana, cannabis, pot or weed plants growing indoors. Source: Author: jeremyn”

You’ll need to match your fan size with your filter and mount it inside or connect it to your ducting pipe. Just remember, the bigger the fan and filter, the more effective results you’ll get.

By the way, carbon filter/inline fan combinations aren’t just great for growing tents. They also work well with space bucket weed-growing operations.

3. Temperature & Humidity Control

There’s a good reason locker rooms smell so bad after a big game or hard workout. The hotter and sweatier the inhabitants are in any room, the stinkier that room will be.

And that doesn’t just apply to people but plants as well. Keeping the temperature and humidity under control will also help control odors.

During the vegetative stage, your plants will require a higher amount of relative humidity than they will when they move into the bloom stage. Once your weed begins to flower, you’ll want to take the humidity down a notch.

A good dehumidifier will help regulate the amount of moisture in the air.

4. Direct Ventilation Exhaust The Right Way & Seal Up Holes

There’s a reason your grow tent came with pre-cut holes, and it definitely was not for you to seal them all up.

Good ventilation isn’t just for your benefit. In order to thrive, your plants need to be raised in an environment with plenty of fresh air and where stale, unhealthy air is filtered out.

If your grow tent doesn’t come with instructions for setting up a ventilation and exhaust system, you can find useful guides online.

Should I Use an Ozone Generator?

Don’t even think about it! Ozone generators are devices that produce the gas ozone, and they can be very effective in processes involving water purification.

However, in order to remove odors from the air, you need a very high concentration of ozone–one that is unsafe for humans to breathe. Some growers may argue that ozone generators can be used if installed in a safe manner, but for our money, it’s really not worth it.

Exposure to ozone can cause severe irritation to the eyes, nose, throat, and lungs.

How to Find & Install the Right Carbon Filter

There are a few simple calculations needed to make sure you have the right carbon filter for the job. Let’s walk through them.

Calculate the Exhaust Diameter

Actually, this is a calculation that in most cases you really don’t have to make. As a rule of thumb, most grow tents are designed with six-inch exhaust holes.

Six-inch fans are an excellent size for generating and redirecting the airflow that most small grow operations need.

Determine the CFM Rating of your Fan and Filter

The CFM rating of a fan is basically the amount of air it can move through a room when run at its highest speed. Your carbon filter should have a CFM rating as well, as this rating is an indication of how much air a filter can handle.

In order for the two to work together efficiently, you should choose a filter that has a rating that either matches or is slightly higher than your fan’s rating.

We explain how to smell proof your grow room

“Growing Marijuana and Cannabis Plants. Source: Author: jeremyn”

What you need is a fan and filter combination that will successfully refresh all of the stale air in your grow tent every three minutes. So how do you determine the CFM needed to achieve that goal?

Simply multiply the width, height, and length of your grow room together to get the room’s volume, then divide that number by three.

Install A Fan and Filter Into the Exhaust System

Once you have chosen the proper sized exhaust fan and carbon filter, there’s just the matter of connecting the two with duct tape and hanging them as high up as you can get them from the roof bars of your grow tent. Then connect your ducting to the outlet of your exhaust fan, again securing it with duct tape.

While there are no special rules to follow, your goal should be to install them in the correct positions to effectively clean the air.


Weed stinks. There, we’ve said it. But the truth is, the more buds you have and the bigger they are, the more your crop is going to stink. So, in a way, that’s a good thing.

Starting your own growth operation involves reading up on a lot of information, gathering the right tools, and making an investment of time and money. If you have the added challenge of needing to do it discretely, addressing odors is a must.

You can mitigate the smell of weed with gels and carbon filters. And you can enjoy some added control by properly ventilating your grow tent and keeping on top of temperature and humidity.

But at the end of the day, if you’re spending time inside said tent, you ain’t gonna come out smelling like roses.

So just keep on enjoying what you do, and maybe while you’re at it invest in some sweet-scented body washes and shampoos. Really now, it’s a small price to pay.