humidity level

Discussion in 'Growing Marijuana Indoors' started by qz420, May 25, 2006.

  1. is it bad that my humidity is at 20% during flowering?? its like 60-70 when the lights off and then 20-30 when the lights on. whats optimal?
  2. You want it low during flower, causes the plant to produce more resins to protect itself.
  3. 60-70 seems pretty high. I'd be worried about mold with that, but I think heat might be more of a problem if there is such a huge difference with the lights on.. dropping all the way down to 20% just from the lights must mean it's putting out some major heat. but as long as the plants aren't burning/drying out low humidity is good for flowering... prevents mold and causes the plant to produce more resin like toasty said.
  4. Hi guys, I know this is an old thread of qz420's but i would like to ask another question bout humidity in my cab.
    Mine was running 15-20% rh, i read in a guide published by SOG Hydroponics they say it should be higher, saying 50% max during flower but didnt say a minimum. Ive now introduced a couple cups of water into my cab and ive seen the humidity rise to 35-40% and an increase in resin on the leaves. I have great ventilation, an extract fan that runs every 15 mins for 15mins whilst the light is on and a top and bottom cooling fan to blow across the buds and under the canopy thats on 24/7.
    I suppose my question is should i take the cups out an go back to low humidity of stick with the new setup? I see most ppl have the opposite problem to what i have and buy de humidifiers.
    Any help appreciated.
    Ta Spud
  5. From my understanding it is better to have the lower humidity for flowering, I'll try to explain why its so. Transpiration is the loss of water through evaporation. To protect the seeds (whether it seeds or not), MJ will produce resin over the buds and small leaves to keep transpiration from happening and drying out the seed. With a higher humidity (50 - 60%) there is little transpiration and little need for resin. Lower humidity allows the water to escape the leaves and MJ will battle this. 35-40% is a good range I would think, but I wouldn't go any higher. Also, with high humidity you're risking bud rot. Stick with you're new setup and if your humidity goes above 40-45% take it out.

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