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Will Open Cell Spray Foam Retain the Growing Marijuana Indoors Smell?
Amanda Ringler

By: Amanda Ringler on November 25th, 2019

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Will Open Cell Spray Foam Retain the Growing Marijuana Indoors Smell?

open cell spray foam insulation  |  marijuana grow room

You can’t miss the smell.

It’s pungent and very distinct – it’s the smell of marijuana. 

Your grow room, whether it’s a free-standing building or in your basement, is pumping out that smell whether you want it to or not. 

Recreational marijuana is legal in 10 states, including Michigan, which means there are a lot of people now growing cannabis for recreational use. While it’s legal, you might not want your home to smell like weed and don’t want people you don’t know to smell your crops in your outbuilding.

With all of this being said, you also want to avoid things that will absorb that smell.

Are there insulation and building materials that will hold that smell? Yes, there is, but some materials like open cell spray foam in grow rooms are getting a bad rap because of its composition.

Will Open Cell Spray Foam Absorb Marijuana Smell?

Here’s the quick answer – open cell spray foam has never been shown to retain any kind of odor.

Here’s the thing. Open cell spray foam is porous, which means it allows water to move through it. There are those who think this means it will hold onto the smell of marijuana in those pores, but that’s not the case.

Foam insulation is basically a plastic insulation material that creates an air seal. These two facts together are what keeps the odor from getting into the foam.

Fibrous materials, like fiberglass or certain drywall materials, are much more likely to have smells get absorbed in them. Drywall is also very porous and has more pathways for the smell to get through. That’s why the odor of marijuana can cling to it.

It all circles back to that air seal, because that is also going to keep some of that smell from escaping.

Marijuana Grow Smell Control

Now that you know that open cell spray foam isn’t going to contribute to the smell of your grow room lingering, we’ve got some tips to combat that odor.

  • Add a carbon filter or carbon scrubber. Carbon filters, also known as carbon scrubber, can pull the smell out of the air and neutralize odors. The filter is great to neutralize the air coming out of your exhaust.
  • Odor neutralizing products in your home, but not the grow room itself. Proper ventilation can only get you so far, as the last six weeks of marijuana’s lifecycle is when it smells the most. Odor eliminating sprays and gels around your home can help mask the marijuana smell.
  • Make sure your temperature and humidity levels are in the right place. Temperatures and humidity that are too high perpetuate odor issues, specifically in the blooming phase, according to Leafly. Maintaining the perfect balance of temperature and humidity for the plants can help reduce the smell. 
  • Grow a strain that has a low odor. Grow Weed Easy recommends growing strains that produce neutral smells not like marijuana even as they reach maturity. 

The Best Insulation for Your Grow Room

Creating an air seal in your grow room is essential to maintaining the temperature and humidity you need to cultivate cannabis.

There are a lot of factors that determine which spray foam you should add to your grow room. If your walls are exposed, then you will want closed cell spray foam because of its durability. If you plan on finishing the walls, then open cell can be installed. 

The key is creating an environment that will be easy to control and maintain so you’re left with a large, healthy crop.

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About Amanda Ringler

Amanda previously has worked as a breaking news and crime reporter, TV news producer, and editor in Flint and Detroit. Throughout her career as a journalist, she has won several awards from the The Society of Professional Journalists - Detroit Chapter and the Michigan Press Association. As part of the RetroFoam of Michigan family, Amanda uses her experience as a journalist to write content that will help educate homeowners on the benefits of foam insulation. When Amanda isn’t writing, she’s spending time with her husband and rescued huskies. She also loves knitting, making art, cooking, and hosting dinner and a movie night for friends and family.