Good air movement is crucial to a successful indoor garden. As was discussed in part one of this article, good circulation strengthens plants, fights off pests, and keeps the air fresh. Now, it is time to take things one-step further. Once you have a stable and controlled environment you can begin to introduce extra carbon dioxide, which can increase yield by 40% or more. This article will cover a few of the advanced techniques that can be incorporated through your ventilation system.

Once your room is stable enough to only need the exhaust fans a few minutes per hour to control humidity and temperature, you can begin to think about CO2 enrichment. The reason you only want the exhaust fans on for such a short time is because you want to keep the CO2 in the room as long as possible. Carbon dioxide exists naturally in the air at around 400 parts per million (PPM). Just doubling this concentration to 800 PPM could increase yield 40%. Most gardeners using CO2 enrichment keep the concentration between 1000 and 2000 PPM. Going over 2000 PPM is wasteful and could be dangerous to the gardener. We offer two ways of supplying CO2 for your room, C.A.P. CO2 Generators and a CO2 regulator with CO2 tank.

CO2 generators burn propane or natural gas, and regulators are designed to attach directly to a CO2 tank. You don't want to have your CO2 charging the room while the fans are going so you will need something to set them apart. Discount Hydroponics offers a CO2/exhaust timer which uses timed intervals. First the fans come on for a set length of time and then immediately following fan shutoff, the CO2 kicks on to charge the room. C.A.P also offers a system in which it is based on temperature, humidity and concentration of CO2. Combining an AIR-3 and a PPM3 does this. The AIR-3 monitors temperature and humidity and insures the CO2 equipment is disabled during an exhaust cycle. This unit also disables the carbon dioxide system during the night cycle because plants do not use CO2 during that time. The PPM3 measures the level of CO2 and maintains a steady concentration based off of your desired level. With these products you can totally automate your ventilation system.

For those who like to use organic fertilizers there are a few odor control devices that can help keep those strong organic smells to a minimum. Our most popular odor control methods are Pro-filters. Each of these can be incorporated into a ventilation system fairly easily. Pro-filters work best with centrifugal fans such as the Hurricane fans. These centrifugal styles of fans are extremely efficient and produce almost no vibration.

While the things discussed in this article can greatly increase productivity in your garden it is important to remember the basics. Ventilation can make or break an indoor garden. Keeping temperatures and humidity stable is primary while CO2 is secondary. Without a good ventilation system, CO2 would be worthless. A well-designed garden room will keep you and your plants happy and hassle free.