By Luke Sholl


Ozone generators are sophisticated machines that allow the conditions in Earth’s outer ozone layer to be replicated. With the ability to annihilate mold, battle pathogens and sterilise equipment, ozone generators present some distinct benefits.

Even better, ozone generators are becoming more portable, and more importantly—affordable. Now, even the novice home grower can take advantage of the benefits ozone generators provide. The trouble is, however, that the equipment is not without a few risks, and depending on your growing setup, the advantages may not outweigh the disadvantages.


Our planet’s ozone layer exists in the stratosphere, roughly 15 to 35 kilometers (9.3 to 21.7 miles) above the surface of the Earth. The purpose of ozone is to capture harmful ultraviolet rays from the sun and prevent them from causing damage. Ozone is made up of three oxygen atoms (O₃). Two of those oxygen atoms form the oxygen that we breathe, and would not be able to survive without. It is the third oxygen atom, the one that can detach itself, that gives ozone some unique properties.

Ozone is an incredibly powerful oxidising agent. Significantly more potent than chlorine bleach, it can be used to remove all manner of free-floating, harmful molecules. This is because the third oxygen atom leaves the molecule and binds with new substances, altering their original chemical composition. Subject a cannabis growing area to ozone, and it can eradicate bacteria, fungus, mold, spores, terpenes (only evaporated molecules), and just about anything biological that could cause a marijuana plant any harm.

Ozone Layer

Ozone generators replicate and produce the triatomic O₃ with a simple flick of a switch, and allow you to pump a grow room full of sterilising molecules. However, ozone can be harmful to humans.

Thankfully, there are ways to mitigate the danger ozone presents, but before we discuss those strategies, let’s take a look at some of the notable benefits O₃ can provide.


• The ultimate disinfectant

Ozone molecules are 2.5 times more effective than chlorine at tackling mold, pathogens, fungi and that dreaded bud rot. Not only could you periodically subject a grow room to O₃ as a means of cleansing your cannabis plants and soil, but you could also use ozone to sterilise equipment, and completely reset a growing area between cultivations. No need to spend hours cleaning down pH meters, cutters, screens, fans or anything else you’ve used.

• Prevents the sweet smell of success from escaping

Some of the risks associated with ozone generators can be avoided by placing them on the exhaust pipes of a ventilation system. Especially useful in areas where growing cannabis may not be strictly legal, ozone generators can be safely utilised to capture evaporated terpene molecules. Terpenes are the compounds responsible for giving marijuana its sweet, seductive aroma. If discretion is the name of the game, then consider adding an ozone generator to the exhaust (not the intake). You would not need to worry about the O₃ molecules escaping outdoors; they would be quickly dispersed.

• Breath of new life into your hydroponic setup

Ozonated water is a fantastic way to cleanse a hydroponic system without having to drain it down and spend hours disinfecting everything. Thankfully, pumping ozone into water is much safer than into the air, so some risk is removed. By attaching an air stone to the ozone generator, entire hydroponic systems can be cleansed by the free-roaming ozone molecules, as they will still bind to harmful pathogens in the same way they would in the atmosphere. You could even use the ozone generator during a grow cycle, to purify both the water and root systems at the same time.


• O₃ is dangerous for our lungs

The first and most immediate disadvantage is that ozone is harmful to humans, even at low concentrations. It does disperse quickly, but even so, breathing in too much O₃ can cause coughing, shortness of breath and chest pains. It also exacerbates existing health conditions, like asthma, which could increase the likelihood of infections. Bottom line—you, and any animals do not want to be near an ozone generator when it is on.

Air Ozone

• The balance between effective and safe ozone levels is challenging to achieve

Several studies have sought to understand precisely how much ozone (measured in parts per million) is necessary to sterilise an environment effectively. However, what research shows as effective is also well into the realms of immediately dangerous to life or health.

Depending on the health organization, the recommended maximum exposure to O₃ is 0.5ppm, although some organizations advise not to exceed 0.1ppm. The American Journal of Infection Control published a study into the topic and found that in combination with low levels of humidity, 25ppm of ozone was needed for 20 minutes to be effective at removing bacteria. If you were to replicate those conditions and take a breath, the levels of ozone would be extremely dangerous.

Additional studies have taken place that suggest a lower level of ozone may be enough to eliminate powdery mildew. However, these recommendations are still at the outer limits of what is considered safe for humans.

• Too much ozone can also damage cannabis plants

Even if you could make sure that proper controls were in place to remove the potential harm caused by O₃, too much can also hurt plants. High levels of ozone can inhibit a plant’s ability to produce chlorophyll, an essential part of photosynthesis. The knock on effect is the death of healthy cells, which will inevitably lead to a plants demise. Too much ozone suffocates plants, and bacteria-free or not, dead plants don’t produce buds.

• It's still an additional cost that can be avoided

It is true that ozone generators have become more affordable, but it is still an additional cost, no matter how small. When you consider that all the benefits provided by ozone can be achieved by having good growing practices, cleaning your equipment by hand, and exercising control of an indoor growing area, only you can decide whether the cost is worth the time-saving.


If you do decide to opt for an ozone generator, then there are a few essential safety tips that should be followed.

The first piece of advice is to pick a generator with an output that suits the size of the area you are growing. If you choose an industrial ozone generator to cleanse a small grow room, then ozone levels will be far too high.

Secondly, ventilation is key when it comes to risk management and ozone generators. Hold your breath when you switch the unit on, and until you leave the room. Once the cycle has finished, ensure you ventilate the room well and leave it to air for an additional hour, so that any rogue O₃ molecules can disperse.

Finally, make sure any LED lights are switched off (the UV rays can interact with the O₃ molecules), and everyone in the immediate area knows that an ozone generator is in operation. You don’t want a friend or a family member accidentally wandering into your grow room while the unit is running.

Health Effects of Ozone


With both the advantages and disadvantages laid out, the decision of whether to include an ozone generator in your grow room will be specific to your circumstances. For the home grower, the risks and preventative steps needed are unlikely to outweigh the benefits. As the size of the cultivation area increases, and so does the length of time needed to disinfect properly, then ozone generators may start to prove advantageous.

If you do choose to opt for an ozone generator remember the safety tips above and make sure it is bought from a reputable producer.

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