Growing Indoors: How to Reduce the Smell of Marijuana with Carbon Filters

Growing Marijuana Indoors
Photo by: Eric Limon/Shutterstock

America is making astounding progress in the world of weed. The possession, use, and cultivation of recreational marijuana is being legalized in more and more states each year, and the number of growers, both amateur and professional, is on the rise. Some gardeners prefer to grow their pot outdoors, while others prefer growing indoors ? be it a tent, a closet, a spare room, or an entire facility. 

Whether you've been growing indoors since before it was legal (don't worry, we won't tell anyone) or you're just starting out with your first seeds, you've probably noticed that marijuana tends to have a relatively obvious odor to it. And yes, that odor is very present during the growing process, not just when it comes to you in bud form. Some people might tell you that the skunky aroma is just part of the package: If you want to grow good bud (especially growing indoors), you have to deal with the smell. But most growers will tell you that there's a great way to reduce the smell of the marijuana you grow indoors, and that’s through the use of carbon filters. 

What Is a Carbon Filter? 

Carbon Filter Charcoal
Photo by: Winai Tepsuttinun/Shutterstock
A carbon filter, which is sometimes referred to as a carbon scrubber, is a large contraption shaped like a tube and filled with a bed of activated carbon granules. This heavy metallic filter comes in different sizes and features the convenient ability to replace the carbon granules within when they need changing. The rate of changing out the carbon granules depends on the size of your filter, the size of your grow room, and the amount of weed you're growing indoors (which directly impacts the odors in the air). 

The purpose of this long-lasting, easily maintained filter is to remove impurities and contaminants from the air using a chemical adsorption process, which means you can (and according to many growers, should) use one to reduce the smell of marijuana when you’re growing indoors. While this article will focus on using carbon filters as air filtration and purification systems, they are also frequently used for water purification by removing chlorine, sediment, taste, and odor (as well as potential volatile organic compounds).  

How Does It Work? 

When utilized as part of an air filtration system, a carbon filter uses chemical adsorption to treat and trap pollutant molecules ? like the ones that carry marijuana's distinctive smell ? inside the tube's carbon granules. Due to the large surface area of each carbon granule, these pollutants and harsh odors are easily trapped within the filter; air passes through the carbon granules, which neutralize any smell and send the air back out into the room odor-free. The efficacy of the filter depends not only on the size of the filter and the amount of carbon within, but also on how quickly the air flows through it. When the air is allowed to flow through the filter at a slower rate, any contaminants are exposed to the carbon granules for a longer amount of time, making for greater odor elimination. 

Is It Easy to Install? 

Before you run out to get a carbon filter for your indoor grow room, make sure you have all of the necessary equipment. That's right ? unfortunately for those of us who just want to grow our weed on the down-low with little effort, carbon filters don't work all by themselves. You can't just stand one up in the middle of your grow room and expect the air to become as clean as the air in Oregon's mountains. In order for a carbon filter to function properly, the air within the room needs to be actively pulled through it. This can be accomplished by using a strong exhaust fan and duct system, which most growers will already have to prevent their room from overheating. Simply install your carbon filter into the exhaust ducts so that the air being pushed out of the room is clean, pure, and free of the smell of marijuana. 

For an incredible step-by-step instructional on how to set up your own exhaust system (including a carbon filter), check out this guide. 

Where Can I Get One? 

Carbon filters are available at a wide range of sizes and prices through various stores and online marketplaces. You can check La MotaGrowers HouseCan-Filters, and, of course, Amazon for a filter that best fits your growing needs. But whatever retailer you choose to buy from, be sure to get a filter that works for your grow room and harvest. There are plenty of online forums available where growers can ask for and give advice based on their experiences. Don't be bashful ? there's a wonderful community of people out there who are ready to help you reduce the smell of marijuana as you grow! 


Are you new to the growing game? Take a look at this set of best practices for growing your own marijuana plants.