The Growing Room
If you want to start growing indoor, the most effective way is by building a special grow room. First of all you will have to decide how big the room will be. It should not be too small since this will limit maneuverability. If you’re growing plants you should be able to move around inside the grow box without any difficulties. The maximal size will often depend on the available space. You could use almost any space: from a small cupboard to a whole room, a garage, an attic.
When preparing the room, you might want to use water resistant foil to cover the floor. If water leaks out, it can cause serious damage, including electric shocks.
Make sure you have access to electricity and water. Also, be aware that if you use fans for ventilation they may make some noise. Therefore, make sure the noise does not disturb any neighbours.
Make sure the grow room is completely light proof. This is essential during the flowering period. When you are running on a 12 hour cycle the darkness must be complete as any light at all will trigger the growth hormones in your plants to either turn on or off. It can be very damaging to your crops if this is allowed to happen at the wrong times.
Then, ensure you have good ventilation, it is important the air goes through the complete growing room. The warm stale air has to go out and fresh air has to come in. You can achieve this by using an inline extractor fan connected to some suitable sized ducting. You can draw in the fresh air from an adjoining room. To prevent mould coming in from this side, you can install a filter in the inlet ducting. Your ventilation system should also eliminate the smell that is produced by your plants. In order to do this, place a carbon filter in the outlet ducting.
Temperature and humidity play a vital role in the growing process. In order measure them, you could buy a thermometer/humidity meter so you know exactly what is going on inside your grow room.
Lighting can cause temperature to rise in your grow room. Therefore, it is important that you ventilation system takes out the warm air and brings in fresh, colder air. At night however, when the lights are out, you have to make sure the temperature doesn’t drop too low. So make sure the room where you draw in the fresh air is sufficiently heated at night.
Humidity is the amount of water vapour present in the air. It is usually expressed as percentage. Low percentage humidity means the atmosphere is dry and contains little water vapour. A dry atmosphere can cause plants to dry out. An atmosphere with high humidity increases the risk of mould or bacteria. If the humidity gets too high, you can extract it by venting out the warm air and introducing cooler, drier air from outside the grow room. If the inlet air is also too warm and humid, you can use a condenser unit (a metal plate which is colder than the surrounding air will cause water to condense on its surface.
If humidity is too low you can increase the level of humidity easily. Just place a shallow open pan of water into the grow room. This will introduce more water vapour into the atmosphere.
The interaction of temperature and humidity in the grow room is fairly simple - the more lights, the warmer the temperature and the more water is lost from the plants. This water from plant transpiration rapidly increases the humidity in the air surrounding the crop to fairly high levels. Therefore the air in the room needs to be vented out and replaced rapidly. When the plants are small, the plant to air volume is large (there is plenty of air and few plants), and less air needs to be refreshed. However, by the time the plants are mature and considerably larger, the plant to air volume is small and many more air changes per hour are required to remove excess heat/humidity. Ventilation is more important during the day - due to the heat build up from lighting equipment, but are also still required at night when humidity levels can still rise because of water loss from the plants.
All of this information might seem pretty technical. The most important thing is to keep an eye on your thermometer and humidity meter and to look at your plants regularly. By keeping a close eye on the appearance of the plants, problems with temperature and humidity soon make themselves obvious.
What lamp do you use? A sodium steam lamp with a full spectrum is good for the beginning, if you gain more experience, you can also use lamps with different color spectrums to enhance vegetative phases (get more out of a plant) and to enhance the flowering (get more potency).
For a first grow only a few square meters are used to grow, therefore a 400 – 600 Watt lamp is enough, you can simply adjust the strength of the light through the height you hang up the lamp. The unit that is used to measure the strength of the light is called “Lumen” The strength of a light on a specific point is measured in "Lux" (Lumen per square meter).