Air Ventilation

When setting up an indoor medical marijuana grow room, making sure you can bring fresh air in and exhaust old air out for air ventilation is very important. The quality of air and Co2 inside your grow room plays a major role in the quality of plant life, as this is what the plant needs to grow. There are 3 major things to remember when setting up an indoor room – air ventilation, stomata and air circulation.

Air Movement and Circulation

Indoor marijuana growing can be very easy if you have the proper air ventilation and circulation, especially the ability to bring fresh air into the grow room. You will need at least one fan for circulation and another for exhaust. Most growers today use a large charcoal filter can fan for their exhaust fan as it not only gets rid of the old air but also scrubs or cleans it, removing the smell from the air prior to exhausting outdoors.

How Plant Stomata uses Air

Stomata are the microscopic pores on the undersides of the leaf that regulate the flow of oxygen and carbon dioxide. The bigger the plant, the more stomata it has to bring in carbon dioxide and release oxygen. The larger the grow room and the more plants you have, the more fresh Co2 enriched air they will need to grow fast. Keep in mind that sprays that leave filmy residues will cause the stomata pores to clog, so always make sure to spray the plants with tepid (hot water mix with cold water) water 2 days after you spray them with any kind of pesticide or miticide spray to help open the pores up.

Grow Room Air Ventilation

Air Ventilation inside your cannabis grow room is as important as water and light are to your plants growth. All marijuana grow rooms need air ventilation, which can be accomplished using a window opening or a door opening to exhaust the air out. Use a squirrel fan or in-line blower to create the air movement or to bring new fresh air into the grow room.

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  1. If I’m running a 600w HID in a say 4X4X7 would sucking air in through a fan at a low point in the tent be enough ventilation, along with running a carbon filter exhaust? it would seem that would be plenty of fresh air,

    • First of all your ventilation space should be sized according to amount of relative humidity and temperature. Plants transpire better when the relative humidity is lower in the growth chamber. this is relative to the temperature in the same area. the higher the temperature the lower you can keep the humidity. always remember. Mold/ fungus can hit you overnight if your conditions are outside of marijuana cultivation parameters. Know your strain and its prime growing conditions are the best. But if you cannot get that remember its ok to have a low humidity. In Alaska, I have to deal with this a lot. So if you live in a humid area be careful and clean. good luck

  2. Need help from HVAC technician.
    Need advise how to set up venting on a perpetual multi room system. Main room is 10×10. Splitting in half makes two 5×10’s. split one 5×10 in half makes two 5×5 veg/flower closets and one 5×10 mom/clone/work area. I desire to have the option to either intake from outside air or basement air depending on outside temps. Would be nice to also be able to shut venting off and create closed system as well. Both 5×5 veg/flow closets will have Co2, carbon filters on fans for exhaust. The 5×10 mom/clone/work area will have no Co2 enrichment. All rooms will be lite exclusively with LED lamps. Environmental controllers will run the show. Any suggestions welcome. Please advise

    • Well you better plan on using manual dampers to regulate the flow of fresh air and exhaust air. one supply can feed all you r growth chambers and one exhaust can do all if you pipe them in a fashion you can regulate/ throttle/balance the air flow that you need. How do you plan on controlling the fans?, remember what you bring in you have to exhaust. What size light are you using? What is your relative humidity there.
      ? How high is the humidity in your growth area? How many air exchanges do you want to go thru in a 24 hour period? How cold is it? How far is the run of fresh incoming air? Can you insulate it if its cold can you heat it? What are your environmental factors?

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