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Marijuana tips & tricks – Prevent marijuana odor

Marijuana tips & tricks – Prevent marijuana odor

Marijuana odor is the number one reason why cannabis crops become exposed. So when a noticeable marijuana odor can be detected in your neighborhood area and you hop into your jaguar convertible everyday high as a kite, people will quickly make the connection. There are always panicky or jealous neighbors that will gossip or alert the authorities when they suspect something. That’s why you don’t talk about it and the good news is that marijuana odor can be prevented. Here are the three most common things that cause marijuana odor to spread and tips on how to prevent it.

Cause 1: No vacuum space
Use a vent fan to extract air from the marijuana grow room. It is important to adjust the vent fan so a vacuum is created in your marijuana grow room or tent. This way you ensure that all the air can escape only through a filter. Test the vacuum by holding thread in the opening of the marijuana grow room or tent and hold the door only slightly open. If you have successfully created a vacuum, the thread will be sucked into the room. If there is no vacuum or if there is excess pressure, it’s possible unfiltered air seeps through holes and cracks. And this you will smell! Make sure there is enough ventilation.

The rules are: the amount of lamps x the amount of Watt divided by 2 = air outlet. And half of the outlet is necessary for inlet. So for 5 x 600 watt you need 1500m2 outlet and 750m2 inlet (5 x 600= 3000 divided by 2 = 1500m2 air inlet). Connect both vent fans to one controller. This way you can prevent activation of only the air inlet, causing excess pressure, due to temperatures measured in different areas of your marijuana growing area.

Cause 2: The wrong filter
With a vent fan that is too small you risk your cannabis crop being exposed. If you have a vent fan for 1500 m³, you must adjust a filter for 1500 m³. Even better is to adjust a filter with 20% more capacity than the vent fan. A filter contains active carbon that neutralizes negatively charged scent ions. When a filter is too small, the vent fan will pull air through too quickly so that the air isn’t filtered sufficiently. The carbon needs time to do its work. Use a filter no longer than one year. After this the carbon is ineffective. You can of course replace the carbon yourself, but keep in mind that this is done with professional equipment, like a vibrating plate, in factories to evenly spread the carbon. It would be wiser not to take any risks and buy a new one.

Cause 3: Leaking exhaust
A small leak is hard to detect, but can cause an extreme amount of marijuana odor. If your filter is attached to you vent fan with a hose, make sure it is secured with clamps. Inspect the hose for holes. Pay good attention to insulated tubes, because the inner aluminum tube contains little holes. It’s best to connect the inner tube to the flange first because this one attaches easily. Now attach the outer insulated part of the hose with a clamp and tape to the box. If you connect the filter directly to the flange of the cochlea, make sure you tape everything really secure into place. If you follow these rules your neighbors should never smell your cannabis crop.

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Comment Section

14 thoughts on “Marijuana tips & tricks – Prevent marijuana odor

By jim on 7 March 2014 at 02:08

Would this work just running it buy you see what you think first grow just putting information that I have collected for my own plan
What I want is a very simple setup up thinking deep water culture 12 or 8 x 5 gallon buckets easy like this In 8’x10′ room in groups or 2 or 3 each under 4 X 1000 watt hps Hortilux bulbs just a straight grow
Is there much advantage to sog or scrog or supercroping what’s your take on those methods would I get more yield from any of these procedures all things being equal in the same amount of space and time?
Could you guesstimate percentage of increase in yield in same amount of space and time?
I read an article that yield is defined by the wattage of light 1 pound per 1000 watts if your lucky is this correct?
Going to be growing White Widow Flowering period: 60 days
Indoor yield: 500 g/m2 And or Holy Grail Kush Flowering Time: 8-9 weeks. Yield: 500-650 g/m2
If one has higher or lower gr/m2 does it matter if indoor yield dependent on light?
I was thinking of cloning for 2 weeks and vegging for 7 = 9 weeks using 4 x 2’ x 4’ fluorescent fixtures = 4 warm bulbs and 4 cool bulbs in the closet bedroom I want to keep the smell in one room
(2 weeks cloning 7 weeks vegging = 9 weeks and 9 week flowering perpetual cycle)
Thus eliminating need and care and room and light for a mother plant
That’s what I’m trying to achieve I will be using 4 x 1000 watt Hortilux bulbs for each 3 x 5 gallon or 2 x 5 gallon DWC buckets want maximum yield with least amount of pails how much harvest could pull from each plant
If maximum yield defined by wattage of light 1 pound per 1000 watts if you’re lucky is this correct?
Would it be pointless have 3 x 5 gallons pails at let say .33333 pounds each or 2 x 5 gallon pail at .5 pounds each?
I’ll never get a pound per light do you think?
Just want room in case I get lucky do you think a 5 gallon DWC bucket will hold a plant that’s been 2 weeks cloning 7 weeks vegging and 9 week flowering without getting root bound
Looking for the magic number of pails
Any criticism or suggestion welcome
PS: I read an article that said one gram per watt of light that’s 2.20 pounds and another article said 1 pound per 1000 watts
What is it?
Thank you in advance for taking the time to answer this
Have a great day

By GrassMaster on 16 August 2014 at 17:59

Jim, you have many questions in your post. Let me start at the top and I’ll do my best to answer them all. First you open up with the statement, “What I want is a simple setup” followed by, “deep water culture”. For your first time grow, I would not recommend a deep water culture system. If you are interested in hydroponics, I would recommend using a soil-less mixture like ProMix HP. Great product. I have used this with much success; producing over 2 pounds with 4 plants in 10 gallon pots under a single 600 watt hps in a 4×4 grow tent.
Next you ask about the potential yield difference between sog, scrog and super cropping. Differnt plants respond differently to those methods. It is going to be something you will have to experiment with over the course of several grows. I would start with topping the plant around the 4th to 6th internode and then topping those new shoots after their third internode. This will give you 4 main tops.
Next I would recommend 4 plants per 1000 watt bulb in a square formation. This will optimize your yields.
You say you plan on vegging for 7-9 weeks? The lighting you have planned will be insufficient. Your fluorescent setup will only last you for the first few weeks of veg at best. After that I would recommend using a switchable HPS/MH ballast and finish out your veg cycle with 1000 watt metal halide bulbs.
One final note… Do not let anyone convince you of what your limits are. I have achieved just slightly over 35 ounces under a single 600 watt HPS. The key is the roots. The biggers the roots, the bigger the fruits. You can have big plants in smaller pots, but you cannot expect that root system to produce incredible yields. Think of it like the water system to a city. A small water main will supply every one with water, but the water will flow at each customers house very slowly. A very larger water main will supply each customer with a larger volume of water. Ever notice that your water pressure drops considerably when 2 people in one house try to shower at the same time? If you had bigger pipes in your house, that wouldn’t be an issue. Both showers would operate at full volume. On that same thought, when 2 people try to shower at the same time in one house and the pressure drops considerably, do you think the pressure dropped at your neighbors house? No, because of the large water main connecting the houses. So in closing, bigger roots (the water mains) and bigger plants (pipes in the house) will produce bigger fruits (full volume at each shower head of the house)! Hope this helps!

By Bi Linnert on 24 June 2014 at 17:18

nice site, enjoyed roaming around a bit.
Question: Is grow boost used in addition to “normal” flower nutes? I typically use General Hydroponics (flora-micro, flora-grow, flora bloom)

By GrassMaster on 16 August 2014 at 18:11

Yes, a bloom booster is used in conjunction with your flowering nutes. Get to know the variety of plant that you are growing. Every plant goes through growth spurts during flowering; each one differently. Learn to time the addition of boosters with those growth spurts and remember to slightly back off on the strength of the other nutrients when adding boosters. Keep records, charts and feeding schedules to dial in your plants and maximize your yields. Hope this helps!

By Poco on 10 November 2014 at 15:50

Sorry – but your rule for outlets makes no sense to me. Your formula yields 1500m2 air outlet. What exactly do you mean by “air outlet”? Is that the vent size? It would crazy huge = nearly 39m x 39m. Is it the volume of the fan/air movement? If so, the units should be in m3 (cubic meters). If it is fan volume, over what time period – per minute, per hour, per day?

By Brian on 29 November 2015 at 07:35

Im trying to grow one plant in a basement bedroom. Im the only one who uses the basement in my home. Will keep door closed and I am hoping that leaving good odor removing automatic air fresheners will make the odor un noticable

Any tips to keep my plant smaller so it doesnt produce as much mass?

By latewood.ILGM on 1 December 2015 at 00:35


You are going to need a carbon filter with a fan to keep the smell down.

In order to keep plant smaller, yiled lower, and be more tame; You use small posts. 1galoon to 6 liters pots will do for entire grow.

You would be better off if you joined our support forum and met all the great growers and staff that help people out. Happy Growing! lw

By Ron on 30 November 2015 at 00:50

Hi Brian, air fresheners really dont cut it when in full flower, I find the best method is by using an ozone generator , no smell at all, but do not go in your room when the ozone generator is on. hope it helps.cheers Ron

By latewood.ILGM on 1 December 2015 at 00:45

You should not have an Ozone generator even in the same room as plants.

By Brian on 1 December 2015 at 06:36

Thanks for replies guys, im new here=)
I am starting at one plant only as a beginner, i trust the seeds im getting from this website will be female

I am researching air purifiers that have Active carbon pre-filters,

sold seperately have Activated carbon and zeolite pre-filters for odor:

I would size it appropriately for my room and replace carbon filter as required.
Has anyone ever had success with this ? most of what ive seen shows it in exhaust systems, but i dont have anywhere to exhaust to really… hence only growing one small plant.

By latewood.ILGM on 1 December 2015 at 00:09

Grassmaster, I like your post, and for re: We call these growth spurts as cycles. My friend Zandor wrote a great article at thegrowreport years back. Search for it. It has a great breakdown and can help you recognize these cycles.

By latewood.ILGM on 1 December 2015 at 00:24


Let me see if I can explain this. The fan is run whenever you need to exhaust heat or humidity into your grow space, exchanging the hot air with fresh air. This is controlled by a temp/humidity sensor and switch, which turns the unit on when heat or RH gets to high.

The size of fan is determined by grow room size and how long you want the unit to take exhausting the room completely. Fans are CFM cubic feet per minute. So you calculate room size. L’ x W’ x H’, and divide the size fan you are using to dertermine how many minutes it will run. (There is no how many times per day, it should run when it is supposed to) For example: Joe Homegrower builds a room that is 15′ x 10′ x 10′ = 1500CF So Joe can use a 1500CFM fan to exchange the air in the room in 1 minute. If Joe uses a750CFM fan, the exchange would take 2 minutes If Joe used a smaller 450CFM fan the room would exhaust in approx. 3minutes 20 seconds.

I hope this clears up the how big, how often questions you had. Peace, lw

By latewood.ILGM on 1 December 2015 at 00:30

I meant to say above…

The fan is run whenever you need to exhaust heat or humidity out of your grow space, exchanging the hot air with fresh air. And to clarify;
Fans are CFM cubic feet per minute. So you calculate room size. L’ x W’ x H’, (IN ORDER TO CALCULATE CUBIC FEET of room), and divide the size fan “INTO TOTAL CF of room), to dertermine how many minutes it will run.

By latewood.ILGM on 3 December 2015 at 08:37

Brian ,

My best advice to you is to do your research and buy the filter you feel would do the best job for you. Since we are not a product testing lab, we cannot truly tell you which unit would be best for you. You have to do the research. WE all use carbon filters and vortex fans; Portable AC units, dehumidifiers; Etc. Etc.

I will tell you this. I have used a carbon filter that sucks out the warm smelly air and a portable AC unit with an exhaust vent that fits a window. This could work for you, if you have a window to insert the AC unit vent into.

You get faster replies and a broader base of knowledge, if you join our Support Forum. Peace :)

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