How Does A Carbon Filter Work In A Grow Room

How Does A Carbon Filter Work In A Grow Room?

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If you are planning to start growing your own marijuana indoors, there are a variety of items that you should have in order to produce the very best results. If you have never heard of a carbon filter before, and you want to grow your own pot, you need to familiarize yourself with these beneficial items.

So how does a Carbon Filter work in a grow room? well, the short answer is they remove impurities from the air which is essential for good growing results (A compound carbon filter is hands down BEST for growing, one that has air ventilation).

Carbon filters come with many benefits for a grow room that you need to know about, so let’s get right to it and cover everything you need to know about these things as there are several different types.

What Is A Carbon Filter?

carbon filter for grow room

A carbon filter is a type of air filter that serves a very specific purpose. Now, there are also carbon filters for water, such as for water filtration purpose, with the end goal of cleaning water for drinking, but that is not what we are talking about here.

Here we are referring to air filtration units. Of course, carbon filters are used in a variety of applications, more or less anything that requires efficient air filtration with the main goal of preventing odors and contamination, such as in a food factory.

Yes, carbon filters are also used for marijuana grow rooms. The purpose of a carbon filter is to remove impurities from the air, and when it comes to grow rooms, this can be quite important in terms of plant health and your overall results.

Carbon filters are chemical media filters and they have the ability to remove odors from the air, volatile organic compounds, and more. There are actually many airborne pathogens that can negatively affect your weed plants, to the point of them dying, and this is something which a carbon filter can help with.

How Does A Carbon Filter Work?

Carbon filters are quite unique in the sense that they use a block of carbon in order to attract and absorb various odors and airborne pathogens. Carbon is naturally good at this, but carbon filters use something called activated carbon.

This is a special type of carbon which has been treated in order to create maximum porosity. Since activated Carbon is so porous, is therefore has a large surface area, and the larger the surface area, the more airborne contaminants and smells it can therefore absorb.

Activated carbon is actually so porous that a single 1 gram block of it has about 500 meters of surface area, or about the size of 2 full tennis courts. Carbon filters work by drawing air through the porous activated carbon, and when pathogens, molecules, moisture, and odors come into contact with the carbon, they are absorbed and neutralized.

So, in essence, the air in your grow room gets pulled through the carbon, therefor allowing it to absorb anything that should not be in the air, and thus keeping your plants much safer and healthier than they would otherwise be.

The 3 Types Of Carbon Filters

Something that you should probably know before you start choosing the carbon filter you want for your grow room, there are some differences you should know about. Here we want to talk about the different types of carbon filters.

As you will notice, there are 3 specific categorical distinctions here, and none of them are mutually exclusive. As you will see below, there are various types of carbon for these filters, various forms of it, and different kinds of carbon filters too.

Once again, these 3 categories are not mutually exclusive and you can get carbon filters that are a combination of any of the components of the 3 categories listed below.

1. Block Carbon Filters vs Granulated Carbon Filters

The first difference that you need to know about here is the difference between block carbon filters and granulated carbon filters. Yes, the carbon in the filter can take the form of small granules, or come as one porous block. Generally speaking the granules are used more for water purification, and the blocks are used more for air purification.

There are various reasons for this, really scientific reasons that are not really worth getting into to be quite honest. However, what you need to know here is that the block carbon filters are more porous and better at absorbing airborne contaminants than the granules are.

Therefore, it is recommended that you get a block carbon air filter, not one that uses granules.

2. Anthracite Carbon vs Activated Carbon

The next difference you need to be aware of is that carbon filters can use different kinds of carbon. First off, you have your anthracite carbon. This stuff is generally used for absorbing gasses and fumes, such as with coal plants.

They are often used for air purification when the combustion of fuels is concerned. There are some of these around which you could use for a grow room, but in all honesty, they are way too expensive and will definitely qualify as total overkill.

Next you have your activated carbon, which is what is generally used for basic air purification, especially for things like grow rooms. Activated carbon is actually just charcoal which has been specially treated to allow it to absorb various air pollutants.

There are various blends of this stuff around, but the most basic forms should be more than fine for a weed growing operation. So, when it comes down to it, we would always recommend using basic activated carbon over anything else.

3. Basic vs Compound Carbon Filters

The other distinction that you have to be aware of here is that there are basic carbon filters. These are more or less just canisters which contain some form of activated carbon which absorbs odors and pathogens. However, these really are not ideal for weed grow rooms, as they have nothing to move the air around and get rid of the old air.

This is why you should go for a compound carbon filter. Compound carbon filters also contain one or more air fans and a venting system. In other words, they actively suck air in to purify it, and then expel it out the rear, usually into venting pipes and out of the grow room. We would definitely recommend using a compound model, as they are much more efficient and better at their jobs than the basic models.

***So, when it comes down to it, for a marijuana grow room, the best recommendation is to get a compound carbon filter that has air ventilation features, which uses the block form of normal activated carbon. This is usually considered to be the best way to go for any marijuana grow operation***

Benefits of Activated Carbon

Just so you know what the benefits of activated carbon are in general, take a look at the quick little list we put together here;

  • It absorbs pretty much any and all vapors.
  • It has a great ability to absorb odors.
  • It has a very high capacity to absorb ozone.
  • It absorbs many chemicals and airborne compounds.
  • It will actually release moisture in order to absorb chemicals.
  • It is totally inert, safe, and fine to handle by hand.

Why Use A Carbon Filter To Grow Weed?

Now, there are actually quite a few reasons why you might want to use an activated carbon filter for your marijuana grow room. It does come with many benefits for the health of your plant, and more.

So, what are the benefits of using a carbon filter in your grow room?

1. Odor Control

First and foremost, if we are talking about odors, there is no denying that a marijuana grow room is going to smell very strongly.

The closer the weed plants get to being mature, as they flower and the buds develop, they will start to have a really potent odor that can be identified from potentially hundreds of feet away.

Depending on where you live, such as in a tightly packed residential community, this can often be quite the problem, especially when parents of children are involved.

An activated carbon filter will absorb the majority of the smell, and therefore keep your grow operation incognito. (the right kind of air fresheners can also help, here is our thoughts on them and our picks).

2. Ozone Absorption

Ozone is very dangerous of course, and it is something which contributes to the creation of smog in cities, and is actually the main contributing factor.

Ozone is also very terrible for plants, especially for marijuana plants in an indoor grow room.

Simply put, having too much Ozone present can kill your plants, and in an indoor grow room, it can build up fairly fast, which makes a carbon filter a big bonus for any indoor growing operation.

3. Eliminating Pathogens

The other benefit that comes with having a carbon filter for your grow room is that it will absorb all kinds of other airborne pathogens, chemicals, and unwanted pollutants.

There are way too many to list, but there are many airborne molecules and compounds which will either stunt the growth of your weed or cause the end result to be lackluster.

Some can even outright kill your plants. A carbon filter can help prevent this in a very big way.

4. Assists With Ventilation

Although not a major benefit when compared to the others, a good carbon filter with an air fan and venting will also help with supplying your plants with new oxygen, creating good airflow, and helping with temperature regulation too, all of which are very important for an indoor marijuana grow room.

What Makes A Good Carbon Filter For Grow Tents – Essentials

Ok, so we have already discussed what kind of carbon filter you should have for your grow room. You should have a carbon filter that uses blocks of activated carbon and has a good air fan too.

Blocks of activated carbon tend to be best for this, and you definitely want the air flow and ventilation properties which a compound model brings to the table.

Are there any other things to look out for when buying a carbon filter for a grow room? Yes, of course there are! (if you want some recommendations then you can read our buyers guide and reviews here).


Ok, so this is related to what we just talked about. Either way, you definitely want a versatile carbon filter that comes with the ability to suck in the air actively and to expel the old air through a ventilation system.


Keep in mind that a really nice carbon filter can run you hundreds of dollars, so your budget is something to keep in mind. If you are only growing a couple of weed plants, a smaller model that uses granules is probably good enough, because they cost less than larger ones that use blocks.

Either way, price is a big thing to look out for, but if you are growing lots of plants, you may as well invest in something bigger and better.

If you are trying to grow indoors on a budget then take a look at this article.


Simply put, you want the best type of carbon available. We would definitely recommend taking a look at some products and what people have to say about them.

Moreover, the shell of the carbon filter as well as the moving components for the ventilation feature should also be made with high quality parts.


Of course, all products will break eventually, so getting something that has a good warranty is always a really good idea.


The size of the carbon filter is also going to matter. Simply put, the larger and thicker the chunk of carbon, and the filter itself is, the better its benefits and absorption capabilities are going to be.

The bigger your grow room, the bigger of a carbon filter you will need. To figure this out, you will need to look into specific products, their capabilities, and what size of space they are built for.

How To Install A Carbon Filter For A Grow Room

Luckily, installing a carbon filter in a grow room is not all that hard, but you will need a couple of tools and a good hour to get the job done.

If you have a closed off grow room, you will need to get yourself some kind of saw like a jigsaw, because you will need to cut a hole somewhere for the ventilation tubes to pass through.

This is honestly a bit hard to gauge, because there are many different setups to go with;

1. With An Integrated Fan & Exhaust

Generally speaking, if you get an all in one compound carbon filter that already comes with a fan system, all you will need to do is take it out of the box, cut the right size of hole in the wall so it fits well, stick in the hole in the right direction, and you are good to go.

Depending on where you want the air to lead to, you might need some tubing to direct the air away from your home or grow room.

You will also want to use some kind of material, something like caulking or fast drying putty to make an airtight seal between the filter unit and the hole you have created.

2. Without An Integrated Fan & Exhaust

If you are buying your carbon filter separately from the ventilation system, you will need to get a fan system that is compatible with it.

You either need to be able to attach the fan to the intake of the carbon filter, so that it blows the air through the filter, or you need to attach it to the outtake, so that it sucks the air through the filter from the rear.

Either way, you need to ensure that the air flow is going out of the grow room, not into it. Once again, the process with cutting the hole in the wall or grow room, inserting the filter into the wall, and using pipes to direct airflow away is the same as with a compound model.

***It is not 100% necessary to have the air coming out of the carbon filter being expelled from the grow room, but it is beneficial. It helps with air circulation and temperature regulation, both of which are crucial for growing marijuana, so we would recommend using tubes, cutting a hole somewhere in the grow room, and directing the old air out of the grow room.***


Ok folks, there we have it, more or less absolutely everything you need to know about using a carbon filter for your grow room. Remember guys, if you are planning a nice grow op, you want to invest in a high quality carbon filter, as it does come with several big time benefits for every indoor grow room.

Yes, it is a bit of an investment, as even lower quality models will cost you a pretty penny, but when it comes down to it, the money you invest in all of your growing equipment will pay off big time in terms of your overall results.