GrowFAQ-Odor control
What methods can I use to remove smells?

The following tips can be used to cover the smell from smoking, or possibly a small grow.
Holmes Odor Grabber or True Air, available at Wal-Mart, Kmart or Target for under $20 US (A more powerful version is available for $29US.) These fan powered carbon air filters work great for small grows. One in the closet or grow room, and one in the adjacent room works very well. Replace the filters once a month (Necessary to keep the carbon active), which cost under $5.

Zeolite (Home Depot). Hang the bag in the grow room. There is also a similar product (“Odour rocks”) used for pet odors, in the pet section at Wal-Mart. Both products are between $5 to $8 US.

Potpourri in electric crock pots. Add scented oils , scented beads, potpourri mixes, spices, you can make it as strong as you like. I keep one near the main entrance of my home, fill it up once or twice and it lasts all day. You can find these near the craft section at Wal-Mart with the potpourri mixes and oils.

Place a small fan with a Bounce dryer sheet laying on the back of the fan, place the fan near your grow. The air is filtered by the scent of the sheet. Many of you may know already how well dryer sheets work.

Ona gel/liquid. Open container and let sit. Removes mild smell for up to two weeks before refilling with Ona liquid is required. The gel can also be placed near a fan (as above)

Glade plug-ins. They work okay, but won’t be enough to cover the smell alone. A few around the house can’t hurt, just change them monthly. Hang some car fresheners all over the place.

The best defense is fresh air. ALWAYS crack a window during the day, even in the winter.

Carpet sprinkle and vacuum products. You will smell it at for at least a few hours, good to use when company is coming over.

Charcoal for use on the bottom of soil, to absorb plant odors. Use an inch or so on the bottom of your soil to neutralize plant odors.

Some other quick smell-busting remedies:
Pine Sol
cook something.
paint something
brew some strong coffee
incense,
scented candles,
spray air fresheners
Add some of the above to your central AC filter, or furnace air intake. Also, dryer sheets work well in a window AC unit’s filter." Try these things in combinations and use often for the best results.

How does ozone control the smell?

Ozone generators are the most effective odor control devices available. Odor is caused by airborne pathogens which float freely and come in contact with our nasal passages. When generated ozone, or 0³ comes in contact with these pathogens one of the oxygen atoms detaches from the ozone molecule, attaching itself to the odor-causing pollutant. This process, in essence, inactivates the odor causing particles in the air, leaving clean, fresh smelling air. Growers report that a good ozone generator will completely eliminate airborne odors from the most pungent crops, but will not affect the dried boquet of the flowers.

There has been some debate over the safety of ozone and humans, however The EPA, USDA and OSHA have approved the use of ozone at concentrations of 0.1 Parts Per Million, for an exposure period of eight hours, without any side effects. Most home ozone generators produce less than .05 PPM, and exposure time is minimal. With this in mind, ozone generation is a safe and effective method of odor control.


What are the dangers of ozone?

What is Ozone?
Ozone occurs naturally in the stratosphere, and at relatively low concentrations. Ozone is the earths main defence against harmful UV rays emitted from the sun. At low concentrations, ozone is harmless, but at high concentrations it can cause problems in certain situations. Ozone is used in the cultivation of cannabis to destroy the tell-tale odors given off by the plants. Ozone is created in 'ozone generators' which can be bought at grow shops, and some household related shops.

Car exhaust is the main producer of ozone at ground level. It's molecular structure is similar to that of oxygen, but the third oxygen atom is unstable, and readily detaches from the ozone molecule and 'attacks' any structure that will accept an oxygen atom. This can be harmful to some organic substances. It's not only organic substances that are affected by ozone. Nearly everything that gets in its way will be destroyed! It is highly corrosive, and can affect everything from metals to rubber. If this gas is so toxic that it corrodes metals and rubbers, just image what it does to your lungs!..

*Ozone is a colorless gas
*It is a naturally occurring gas
*It does not have an obvious odor (although some say it smells like fresh rain, or purified air)
*Ozone is a toxic gas How does it affect me, and what are some symptoms of over-exposure to ozone?

Short exposures of relatively high amounts of ozone (found in some grow rooms) can cause problems such as:
*Pains in the chest
*Throat irritation
*Coughing
*Shortness of breath

Although short exposures to ozone may cause problems, these should clear up over time. Prolonged exposure to high concentrations of ozone can cause severe damage to the lungs and other parts of the respiratory system, and over time may have irreversible effects. The more ozone a person inhales, the more damage is done to their system, and the less chance there is of recovery.

People with asthma are advised to avoid prolonged exposure to ozone, as it may cause an 'asthma attack' or flare up problems with their respiratory system. As an example to the severity of ozone 'poisoning', the New York State Ozone Advisory will issue a warning to people if the level of ozone is above 0.08 ppm for more than 8 hours at a time. 0.15 ppm is intolerable for even short periods.

What can I do to prevent over-exposure? You're ozone generator should not pumping ozone directly into the room. If you are using an ozone generator, us it in conjunction with your ventilation system. This way, no concentrated amounts of ozone are present in the grow room, but instead having all the ozone flow in the exhaust tubing to clean the air as it leaves the grow room.

Put your ozone generator inside your exhaust ducting - most generators are round tubes with 4/6/8" diameters, designed to work inline with your grow room air exhaust system. Some generators have a control that regulates the output levels (The generator functions at 100% output, but this rheostat cycles the on/off cycles, much like a microwave). This method is the safest and most effective way to use your ozone generator, but for added advantages, if you divert some ozone back into the grow room it will help kill airborne substances such as spores, moulds, etc to help keep your grow sterile and clean.

If your generator is pumping ozone directly into your grow room you will need to have a strong ventilation system to help keep the levels of ozone from building up to dangerous levels. Having the exhaust air vented outside is the best solution. Avoid spending excess amounts of time in your grow area if you are using an ozone generator. Concentrations (according to various controlling bodies) should not exceed concentrations of 0.10 ppm for more than a few hours at a time. It is also understood that these concentrations and below are not suitable for controlling odors. This means that if your grow room has an odor problem, and you are using an ozone generator, it is highly likely that you are exposing yourself to harmful levels of ozone. If you run your ozone generator on HIGH in a relatively unventilated area, you can easily reach levels of 1ppm, which is 10 times higher than the maximum recommended level.

Ozone alternatives In general, DO NOT USE AN OZONE GENERATOR UNLESS THERE IS ABSOLUTELY NO OTHER SOLUTION TO YOUR ODOR PROBLEM! Do not think of an ozone generator as an easy way to control odors, because you could be putting your own personal health at risk!

Cheaper types of ozone generators may use crappy materials in their design, which can cause more problems. The corona discharge method is particularly bad, as the cheap alloys used can give of dangerous oxides. The smell from this may have a 'metallic' scent to it, so keep that in mind when purchasing an ozone generator (or making one, which is not recommended). As a rule, the materials used in an ozone generator should be as unreactive as possible, such as steel, gold and silver.

There are some alternatives to ozone as an odor controller, the main one being the 'UV ionizer' and the 'carbon scrubber' which uses activated carbon to remove odors. These options may not be as effective as ozone in some situations

How do ionizers compare to ozone generators?

Not very well. The typical product sold at Wal-mart as an "ionizer" is usually a fan, air-filter, and inefficient needle ionizer. They hardly put out enough to cover a 70 watt cabinet. There are more serious ionizers available that could cover a low-smell 400 watt garden but anything more than that and you really need to invest in a good ozone generator or save some money and make your own.

How to build an inexpensive carbon air scrubber? (incomplete)

Building a carbon scrubber for de-odorizing stinky grows. The design is such that there is no back pressure on the grow box exhaust fan, and there is maximum surface area for the exhaust air to contact the carbon. The basic parts list: 2"x2"s and 1/4" plywood sheets, cut to the size of the furnace filters being used 4 furnace filters 4 to 5 lbs. of activated carbon A set of four casters (wheels) Duck tape, screws and four *hanger bolts 2" long by 1/4-20 with wingnuts and washers to fasten one removable side for filter servicing. *Hanger bolts are machine threaded on one end and wood screw threads on the other end. It starts with the frame construction: In this example, the measurements of the box, furnace/fibre filters etc... the scrubber is ~ 17" x 26" x 48" tall... the furnace filters are 16" x 25" x 1", though they are really only 3/4" thick. But again, your design dimensions will depend on the furnace filter size you choose based on the design criteria. Wheels for mobility, and a wire screen on the bottom to hold the weight of the de-odorizing filter without the filter buckling. Using 4 furnace filters and 4 1/2 lbs. of activated carbon to make a dual layer de-odorizing filter. 2 furnace filters on the bottom, then a layer of carbon, another furnace filter, another layer of carbon, and a furnace filter on top. Tape up the carbon/screen layers, and then tape to the base, creating a completely sealed bottom. Add the walls and top. Precut the input air opening before attaching the sides, and add appropriate interface hardware. Tape up the box seams with duct tape (the metal tape is best), and it's ready for action. Design criteria and further comments. The design is solid and works well at eliminating that smell as long as the following criteria is observed: For every one (1) cubic feet of exhaust air to scrub: Have a minimum of 1.25 ounces of activated carbon. Have at least 8 square inches of filter surface area. The concept has been tested for several months with multiple grows of the smelliest stuff available. not only does it work well during the grow, but the same technology has been used successfully in drying chambers to eliminate the odor of drying bud (sometimes far worse than the grow itself). Ionizers are a waste of money to ganja growers. I did try the design with an ionizer inside the enclosure, no difference. I have also used ozone and found it to be very effective in conjunction with carbon for larger grows where the design criteria could not be met (too much air flow for the filters used), but the ozone is after the carbon and not before, since carbon absorbs ozone, and i want the carbon to saturate as much as possible with bud stink, then the ozone to clean up the rest. The carbon is changed every three (3) months or so, and so far, it has not reached saturation within that time period. Some Q & A about the carbon air scrubber Why is the box so big? To eliminate back pressure on the exhaust fan to maximize air movement through the grow box. I am sure the overall dimensions can be scaled down, though I am not sure to what dimensions. Could you do this to a regular grow box? Yes, although you want all of the workings in the top of the box. Exhaust fan, carbon filter, etc., venting out of the top of the enclosure. Where did you purchase the carbon? The neighborhood fish/aquarium store has the pricey stuff, at around $10+ per 2.25 lbs. It comes alot cheaper, though you might have to change it out more often. Mail-order fish supply places over the net are the way to go when purchasing bulk activated carbon/charcoal.