How to control the smell of indoor cannabis

Cannabis plants will always have a distinct smell attached to them. It’s an aroma that sets it apart from other plants, and is easily recognisable to any herb lover.

Now, that scent has its pros and cons. If you love marijuana, it’s a sensation in the air you wouldn’t want to dissipate. But, what if you’re living with people who don’t have your same appreciation for the herb? Or worse, what if you’re living in a place where it’s illegal to grow cannabis? Either scenario could give you problems.

No perfume or deodoriser can mask that trademark cannabis smell completely. But, in this article, we’ll present you with some proven strategies to deal with this situation effectively. But first, let’s examine what cannabis smells like, and why it has this odour in the first place.

What Do Cannabis Plants Smell Like?

Ask anyone to describe the smell of a cannabis plant, and you’ll get different answers. Some will describe a musky odour comparable to a skunk, whereas others will cite an earthy smell reminiscent of a grassy field or pine forest.

The truth is, different cannabis strains exhibit a range of scents depending on their chemical makeup. If you’re a weed grower, one thing you’ll notice is that cannabis plants don’t smell the same throughout their life cycle. During the earlier days of the growing process, the smell isn’t as pungent.

But once plants enter the flowering stage, signature dank scents will soon build up, and can quickly overtake an indoor (or outdoor!) growing space.

Now, if you’re buying your weed (i.e. you didn't grow it yourself), you’ll encounter a slightly different scent from the one the growers experienced. This is because the buds are cured after harvest, which subtly changes their flavour and aroma.

To a degree, the longer the buds have been cured, the more intense the smell gets.

Why Does Weed Smell the Way It Does?

Not all cannabis strains are created equal. In terms of aroma, each one will have detectable differences. The most crucial factor determining a strain’s aroma are the terpenes present in a given specimen.

With over 200 terpenes in cannabis, their presence, and concentration, is the reason some strains smell fruity or floral while others smell spicy or earthy. Terpenes not only exist in cannabis, but in many aromatic plants. These compounds are basically the IDs that create the specific scent and flavour profile of each strain.

Below is a list of cannabis terpenes and their corresponding aromas:

• Limonene: Citrus, lemon
• Myrcene: Musky, earthy
• Caryophyllene: Woody, spicy
• Camphene: Damp, woody
• Pinene: Pine, fir
• Linalool: Lavender, floral
• Terpinolene: Pine trees, herbs
• Phellandrene: Citrus, peppermint
• Humulene: Hops, beer-like
• Sabinene: Pine, orange, spice
• Geraniol: Rose
• Terpineol: Flower blossoms, lilac
• Carene: Sweet, pungent, fir
• Pulegone: Peppermint

When Does It Start To Smell When Growing Weed?

During the early stages of cannabis plant development, you won’t detect much of an odour at all. After all, it’s the buds that are chiefly responsible for the dank scent. As such, most plants won’t start to smell until the flowering phase has begun and terpene production is ramped up in the trichomes (tiny mushroom-shaped growths that produce cannabinoids, terpenes, and other compounds).

However, there are cases where cannabis plants will smell even during the vegetative stage. You see, even cannabis fan leaves contain small amounts of terpenes and other molecules, so it is possible to have a smelly specimen just a few weeks into vegetation. That said, the smell will always be at its most intense during late flowering, right before harvest.

Size and volume also play a role in the intensity of a plant’s scent. Large plants with a huge canopy of buds are more likely to stink out a grow room than one small specimen. Moreover, some plants are just more pungent than others, and vice versa.

Can the Smell of Cannabis Go Through Walls?

You’d be surprised at how often people throw this question around. And, according to one Winnipeg-based family, it apparently does.

The family wrote in to Winnipeg Free Press to complain about the weed smell coming from the townhouse adjacent to theirs. With only concrete walls separating the two houses, they were befuddled at how the scent managed to crawl into their home.

Their concern is that their house now “smells like a marijuana shop”, and that their young children are breathing it all in. An air purifier, they said, didn’t help.

Odour Control: How To Hide the Smell of Indoor Cannabis Plants

Now, let’s proceed to the solution to this family's problem, and everyone else facing this issue. Here are four ways to neutralise the smell of indoor cannabis plants.

Install Activated Carbon Filters

If you have a grow room, activated carbon filters are your best bet in eliminating cannabis plant odours. These “carbon scrubbers” are known to absorb any weedy smells in the air, as well as other airborne impurities, thanks to the presence of activated carbon.

For indoor growers living in areas that have yet to legalize cannabis cultivation, a carbon filter is an absolute necessity for ensuring your grow-op remains low key.

What You Need

• Carbon filter (300 to 400 CFM rating)
• 400 CFM fan
• Two ducting hoses

Experts recommend a standard measurement of six inches (~15cm) for the carbon filter, fan, and hose. It’s because six-inch fans are capable of providing enough air exhaustion for most small-scale cannabis grow rooms. The filter and ducting hose need to be the same size to work effectively.

How To Do It

• Place the carbon filter behind the exhaust system. This will help to prevent the smell of your cannabis plants from seeping out.

• Connect the filter to a ducting hose, then attach the hose to one end of the hood of your grow light.

• Attach the fan to the other end of the grow light hood. Finally, attach the other ducting hose to the fan.

Use Odour Neutralisers

If you’re dealing with neighbours getting wind of your cannabis plant smells, an odour neutraliser is your best immediate option.

Unlike carbon filters, these products don’t eradicate odours. As the name suggests, they act as neutralisers that bind with the marijuana smell. They do so by emitting strong fragrances to mask unwanted odours.

What You Need

• Odour-absorbing gels or sprays

How To Do It

Because odour neutralisers emit fragrances, it’s advised to use them outside of your cannabis grow room. The gels tend to be very effective, but they can be strong enough to alter your buds’ flavour.

With the spray, you’ll definitely want to avoid using it near the plants, especially during the flowering stage. That synthetic fragrance may stick to your buds and compromise the flavour—not good.

Keep the Air Moving

A lack of proper air circulation could be another reason you’re stinking up your home with marijuana plant smells. Your grow room gets filled with little pockets of hot air, which causes these odours to become more noticeable.

So, if you want to minimise cannabis plant odour in your home, keep the air in your grow tent/room moving.

What You Need

• PC fan or any oscillating fan
• Ducted intake
• Exhaust fan

How To Do It

Place the fan next to your plants, about a foot or two away. You’ll want an oscillating fan to effectively circulate the air and allow the plants to breathe.

A small desk fan will work for a regular cannabis grow room. If you’re working on a smaller scale, a PC fan should do the trick.

But remember, aside from blowing air around, you need to ensure you have an intake and exhaust system set up to allow air to move in and out of the grow room.

Keep Temperature and Humidity in Check

Lastly, always make sure that your grow room’s temperature and humidity levels are in check. Having both on the high side may intensify the smell, especially during the flowering stage.

What You Need

• Fans
• Dehumidifier
• Air purifiers
• Air conditioner

How To Do It

As pointed out previously, oscillating fans are great for air circulation and temperature control. They get the job done in terms of lowering humidity levels, as a dehumidifier would also do.

But, if you’ve already built yourself a grow room, the next sensible step is to invest in an air conditioner. It’s the best tool to keep heat, humidity, and plant smells under control.

How To Get the Weed Smell Out of a Grow Room

So far, we’ve covered ways to mask or neutralise the smell of cannabis plants while they’re growing. But, how can you clean the weed smell out of your grow room once harvest has come and gone?

Here are some simple methods you can use, whether you’re working in a spacious area or a smaller grow space.

• Clean your walls: With the help of a cleaning solution (aka warm water, distilled white vinegar, and soap), scrub your walls using a rag. Afterward, dilute it using clean water.

• Clean your carpet: Sprinkle some baking soda onto the carpet and leave it out for a day or two. Clean it out using a vacuum cleaner once done. If that doesn’t work, then it’s time for some shampooing.

• Dust the furniture: For wooden furniture, use a soapy solution to wipe it down. For those with fabric, use the same baking soda technique as you would with your carpet. A cleaning solution of white vinegar, water, and baking soda also works for worse cases.

• Clean tighter spaces: Begin the process using a vacuum cleaner to eradicate small weed particles. Next, rub down all hard surfaces with a simple soap and water solution.

• Remove weed smell from fabric: Apart from the baking soda option, you can use vinegar to take out unwanted cannabis odours from fabrics. Mix the vinegar with some hot water for washing, or use the highest temperature on a washing machine.

What Are the Best Low-Odour Weed Strains?

Another way to limit the smell of marijuana is to opt for low-odour strains. These are high-quality cultivars that won’t sound any alarm bells with their scent.

Doing a Google search may lead you to an overwhelming assortment of options, so we’ve narrowed it down for you.

Northern Lights

Everyone loves the fresh scent of pine trees, especially in the early morning. That’s the exact vibe that Northern Lights brings. Luckily, in the grow room, plants keep this aroma on the subtle side.

This indica-dominant strain will leave you relaxed and buzzed, but not too stoned for social situations. You’ll definitely feel its 19% THC level; whether you intend to go on a philosophical dive with friends or binge-watch your favourite TV series, this is a perfect companion to have.

Northern Lights is also a grower’s delight. With a 7-week flowering time, it delivers 500g/m² indoors, and an equally large yield outdoors.

Polar Express

If you read the strain description for Polar Express, you’ll discover it has a skunky, piney profile. But, in reality, it gives off very little aroma, making it a perfect strain for discreet growers.

This indica-dominant cultivar offers a distinctly euphoric mind–body high that is equally relaxing as it is inspiring. It, like Northern Lights, is a popular option among holistic cannabis users.

Growing to just 30–80cm in height, Polar Express really is the perfect stealthy strain. And when harvest comes around, you’ll get to enjoy up to 400g/m² indoors.

Jack Herer

Jack Herer is another favourite among low-key growers.

Named after one of the most significant cannabis activists in history, this strain gives off a fruity, peppery aroma that’s far from overpowering or offensive. That should help in preventing unwanted attention from neighbours.

With a 50/50 indica/sativa balance and 17.5% THC, Jack Herer will leave you with just the right amount of cerebral buzz. It also brings some uplifting effects, making it a great ally during daily activities—even workouts.

If you’re a grower, working with Jack Herer is a breeze. With a flowering period of up to 70 days, you can expect plants to reach over 2m in height and deliver impressive indoor yields in the region of 600g/m².

Growing Cannabis Indoors: Can the Smell Be Problematic?

Indoor cannabis growing will always be a smelly venture. Depending on your situation, it could give you some problems down the line.

If you’re looking to eradicate unwanted odours, keep these general tips in mind:

• Take the necessary steps to control odour. Some tools that could help you out include carbon filters, odour-neutralisers like gels and sprays, and fans.

• Be sure to keep humidity and temperature levels in check. The higher these numbers are, the more intense the smell.

• There are low-odour cannabis strains you can go with, such as those listed above.

• Keep your grow room well-maintained. Regular dusting and cleaning sessions should help minimise the accumulation of unwanted smells.

The smell of growing cannabis indoors shouldn’t be a cause of headaches for you. If you regularly take the necessary steps and preventive measures, you can achieve a successful harvest without a hitch!

There’s no way around it: cannabis plants smell! And while you might love your green ladies’ perfume, there are plenty of people who don’t. Hence, it’s important you keep the smell of your indoor grow to a minimum.