Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

by a solenoid valve and a short-term timer. With such a system, CO 2 could be released periodically in small increments and coordinated with ventilation schedules.
    Note: Some recipes replace vinegar with muriatic (hydrochloric) acid. I advise using vinegar, because hydrochloric acid is very dangerous. It can burn flesh, eyes, and respiratory system; it can even burn through concrete.
Odor
    A good exhaust fan, vented outdoors, is the first step in cannabis odor control and the easiest way to keep the house from reeking of fresh marijuana. If the odor is strong and venting is a problem, a negative ion generator (deionizer); deodorizing liquid, gel, puck, or spray; ozone generator; activated charcoal filter; or a combination of two or more of these will solve fragrance problems.
Deodorizers
    Kill odors by changing their structure at the molecular level. Products such as Odor Killer™, Ona™, VaporTek™, and Ozium™, are made from essential oils that kill odors by creating a neutral atmosphere at the atomic level. Such products are usually available in gel and spray. Many growers prefer to use the gel over the long term and spray for emergency situations, such as when unexpected guests stop by during harvest.
    The deodorizers can be set out in the room, around the house, and near doorways. Several companies offer products that stick to the wall. One ingenious grower I interviewed stuck one such deodorizing puck to the inside of the front door, just below the mail slot to keep the house fresh. Other products are designed to be attached to the ventilation ductwork system. Often these products are used not only to alter the odor of marijuana, but also to alter the telltale odor produced by an ozone generator. Other companies offer aerosol spray cans with a dispenser that periodically meters out a burst of spray.
Negative Ion Generators
    Negative ion generators are small and somewhat efficient to control odors, smoke, airborne pollen, mold, dust, and static electricity. They pump negative ions into the atmosphere. The negative ions are attracted to positive ions containing odors and other airborne pollutants. The negative ions attach to positive ions, and the odor becomes neutralized. The particles fall to the floor and create a fine covering of dust on the ground, walls, and objects in the room. These devices work fairly well for small grow rooms with minimal odor problems. The generator uses very little electricity and plugs into a regular 115-volt current. Visually check the filter every few days, and make sure to keep it clean.
Ozone Generators
    Ozone has many applications including food and water sterilization and removing odors from the air at the molecular level. Some growers even use high levels of ozone to exterminate grow room pests.

Although a bit of a trick to keep going all the time, pouring vinegar on baking soda is a fair source of CO 2.

Some gardeners prefer to use essential oils to overpower fragrance. Such products are available in liquid, gel, and spray forms.

Fan with deodorizer

This grower treats the air with ozone and deodorizes air again just before it is expelled.

    Ozone generators neutralize odors by converting oxygen (O 2 ) into ozone (O 3 ) by exposing the stinky air to ultraviolet (UV) light. The extra molecule is always a positively charged ion that is predisposed to attach to a negatively charged ion (cation). Odors are negatively charged cations. When the extra oxygen ion attaches to the cation, they neutralize one another and the odor, too. Once the extra molecule is shed, O 3 is converted back into O 2 . The chemistry takes a minute or longer to occur, so treated air must be held in a chamber to be converted effectively.
    Ozone has an unusual odor similar to the smell of the air after a good rain. Anybody who has ever smelled the air in a room recently treated with ozone knows the smell and will never forget it. Make sure not to produce too much ozone, and give it enough time to mix with smelly air to neutralize odors. The distinctive odor of excess ozone exiting a building will tip off narcs and thieves. For this reason, many growers also use a carbon filter to further scrub the air.

Ozone generators are rated by the number of cubic feet (m 3 ) they are able to treat.
    There are many ozone generators available. When shopping for an ozone generator, look for one that has been on the market for a few years and has an established track record. Watchfor important features such as