Ozone - THE GROW ROOM SUPER-TOOL
Ozone generators are becoming more affordable every year, and are a common feature in larger commercial grow rooms to knock out unwanted odours escaping. However, Ozone is so much more versatile than just smell prevention. Domestic and industrial use of Ozone is not new, but translating the many benefits into a grow operation deserves a little attention. !


- Keep all pets away from the 0zone generator while it’s running, and for an 1 hour after it’s been switched off.
- Get everything else completely ready before you switch on your Ozone generator – it should be the last thing you switch on before quickly leaving the grow room.
- Always connect it to a timer to switch it off after it’s finished. Some generators have a built in timer, but experience says they can often break on the cheaper models, leading to high levels of unexpected Ozone
- build-up. Better to be over cautious.
- If you really must re-enter the room while the Ozone generator is running, hold your breath. Ozone is safe to humans if you don’t breathe it in. Make sure a friend is there too, just in case you fall over or something.
- Consider buying an 0RP sensor (0xidation Reduction Potential) to monitor safe Ozone levels in your grow room.
- If just using the generator to oxygenate water or oil, consider running it in an outbuilding.
- Close the door of your grow room to keep the majority of Ozone contained.
- Tell anyone else in the house before you use Ozone, so they can also stay clear of the room.
- 30 - 45 minutes after the 0zone generator is switched off, all the Ozone will have disintegrated into normal oxygen so the room will be safe, but still smell incredibly clean. Personally I leave it for 1 hour just to be safe.
- 0zone is a fantastic tool, but it must be respected & used carefully. Some Ozone generator manufacturers gloss over the potential safety risks, so please be careful. DO NOT BREATHE IN OZONE!

The most common use of Ozone by growers is using them inside the ventilation ducting inline with a carbon filter. This gives an extra insurance against unwanted odours escaping into the wider world. Using Ozone in the ventilation ducting works great and is a “belt and braces” addition to odour control. The Ozone molecules má with the smelly plant terpenes inside the pipe, neutralizing them & guaranteeing a no-smell, no-tell situation outside. This method is also the safest, as no Ozone buildup is possible inside your room, but you must be careful not to vent Ozone-heavy air somewhere it could cause harm to people or other vegetation.
For this setup you would need a medium output inline generator to place inside your ducting after the fan. Because Ozone is heavier than air, allow the path of the ducting to drop to the floor after the fan & generator stage so when the ventilation system is switched off, residual Ozone will stay in the dip & won’t leak back into the room. In an ideal world you would have this inline Ozone system as well as a more portable Ozone generator.
Ozonated water.
If you have an Ozone generator with the tube and air stone option, then you can ozonate water too. This is a fantastic way to ensure your root zone stays healthy (which in turn makes your buds swell up), and also lets you disinfect a hydroponic system with your plants still installed.
Working with Ozonated water is much safer than using it in the air. When Ozone is bubbled through water, the unstable molecule behaves as it does in the air; attaching itself to any single celled pathogen and killing it instantly. The by-product of this is pure residual oxygen in the water. Once all the pathogens are gone, the Ozone actually starts to be absorbed into the water too, where you can harness it’s power inside the rootzone. When using a 400mg Ozone generator, place the air stone at the bottom of your water container and ozonate for around 2 minutes per liter of fluid. If possible do this in your porch or outbuilding so you don’t have to worry about breathing in the Ozone. Use the water right away, as the Ozone starts to break down into oxygen over 30 minutes. Water won’t absorb Ozone to toxic levels. Once you have Ozonated water you can really do some amazing things with it:
- Spray it directly on your plants to kill any spores, rust spots, fungus, powdery mildew or bud rot. Unlike commercial sprays It is safe to use at any time in the flowering period, as you are not introducing any chemicals at all. Of course it is still a good idea to keep humidity low & avoid spraying too much during flowering.
- Immediately dip fresh cuttings in the Ozone solution for 30 seconds to sterilize them before dipping in rooting hormone. This improves strike rate dramatically.
- Dip all your pots, syringes, pipettes, meters, drippers, pumps, connectors and anything else that goes near your plants in the Ozone solution for 1 minute to sterilize them safely.
- Pour it straight into your root zone to give a massive oxygen boost and sterilize the rhizosphere. Bear in mind that it will kill any beneficial bacteria too, so you will need to replace any Trichoderma or similar that you’ve used.
- When you change your solution, ozon-ate the fresh nutrient solution thoroughly before running it through the system, disinfecting everything and giving the plants a huge oxygen boost.
- Clean your bong with it. It will smell great!
Working with Ozonated water is much more forgiving than in air. You can safely handle it, and people with skin complaints may actually find it helps a lot, as it gently keeps your skin sterile.
There is no point in using organic nutrients or supplements in freshly Ozonated solution, as the Ozone will kill any beneficial bacteria too (including trichoderma). If your supplement isn’t compatible with Liquid Oxygen, then it’s not compatible with freshly Ozonated water either. But because Ozone only remains active in water for around 30-45 minutes before turning back to oxygen, you can still use organics if you wait for an hour or so after running the Ozone through your system, & get the best of both worlds.
No more fear of bud rot!
Probably most exciting to growers is the fact that an Ozone generator can save your crop from budrot, even if it’s already started to weave it’s evil grey web around your precious buds. Better still, it does this quickly without adding any toxic chemicals at all.
- At the first sign of bud rot, physically remove any infected material from the room (you can spot budrot before it really happens by looking for a single leaf in the bud that is a little darker & browner than the others around it. Check this spot as you have probably got the first signs of budrot)
- Switch off your extractor fan but leave your circulation fans running. (You will need to set a timer to switch your extractor back on in about 15 minutes). Also lower the light output to avoid heat build up while the ventilation is switched off.
- When using a 400mg per hour 0zone generator, try running the Ozone generator for 30-45 seconds per Meter cubed of enclosed grow space then switching it off. If you have a machine with a tube outlet, you can attach it directly to a circulation fan for maximum spread.
- Leave theextractorfanoffforl5minutes afterwards, but make sure the circulation fans are moving lots of air around inside so the Ozone has a chance to touch all the nasties.
- After the 0zone generator has been switched off for about half an hour with the extractor fan switched back on, open your tent and look at the mould – instead of looking grey,
- vibrant and fluffy it should now look brown, crusty and dead – victory!
- If the mold is more serious &progressive, then you may need to run the Ozone for longer. For serious infestations in large rooms, up to an hour without the extractor on. In these situations then it is important to do it in the plant’s “night” period, to avoid heat from the lamps building up while the extractor is off.
- You will still need to dispose of any previously infected matter, as although the mold is no longer active, you still wouldn’t want to smoke it.
Inspect every plant thoroughly, and if there is any mildew alive, or you see the any more little leaves between the buds going brown, repeat the process. Beware that building up too high a concentration of Ozone in your room can actually cause plant damage to the stomata, resulting in burnt leaves, especially at the tips & wider shade leaves closest to the generator. There have also been reports of it damaging the delicate trichomes of resin on the buds with major overuse. If you tread carefully using it little and often, your plants will be OK.
You may still have to toss a few buds if they were infected already, but the mould will not spread and you have saved your crop from death or early harvest. Check your buds for new mold thoroughly every day for a week just in case it’s a systemic infection, & if you spot any new problems then repeat the process. It is better to treat little and often, than risk causing Ozone damage to your plants...Although of course it’s debatable which is a worse problem to your crop – mould or Ozone damage.
Battle spider mites!
If you have them, spider mites are the bane of your life. They spread fast and are tough to beat. Where all else fails, Ozone will get them. A higher level of Ozone will break down their respiratory system & kill them. The molecular Jean Claude Van-Damme is back to kick butt! The levels you need to run the Ozone at to kill spider mites will probably cause some plant damage, but spider mites can cause worse! It is an emergency option for heavy infestation, & in my opinion preferable than chemical alternatives. Always be safe & never breathe the Ozone. Safety is more important than a crop.
Other applications for an Ozone generator.
You can also bubble Ozone through oil and it apply directly to the skin. Unlike water, which only holds the Ozone for a short time, oil retains the Ozone for much longer – anything from 30 days to 6 months or even more, depending on the level of ozonation.
The benefits of Ozonated oil include:
- greatly improved healing time for skin wounds & ulcers
- topical anti-bacterial & anti-fungus which helps prevent infection
- it's good for wounds on pets as it is natural & safe for them to lick
- great for any kind of yeast infection
- ringworm
- sunburn
- dermatitis
- haemorrhoids.
You can Ozonate whatever oil suits you best - great results have been achieved from ozonating olive oil, jojoba oil, sesame oil, peanut oil, coconut oil, and many more. There are two levels of Ozonated oil - Partially or Concentrated. Partially Ozonated oil is by far the quickest & easiest to make. You bubble your 500mg/hour Ozone generator through the oil using an Ozone-proof airstone (glass is best) for an hour minimum. This is a time when more is better, so you can keep going for several hours or even overnight if you want. It is impossible for the oil to absorb Ozone to toxic levels, although of course you should still be mindful of the ambient Ozone levels to avoid too high a level in confined spaces.
Concentrated Ozone requires an industrial Ozone generator capable of producing over 4 grams of Ozone per hour. You also need to bubble it through the oil for three weeks. On balance I’m guessing the home producer may be better sticking with the Partially Ozonated Oil!
An Ozone generator is a wonder-tool for the hydroponic gardener, & if treated with respect will solve many of your problems & maximise your efficiency.