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low humidity

Discussion in 'Growroom Design & Setup' started by clandestino, Dec 3, 2008.

  1. running 9 600w lights in my flowering room and the humidity is dropping to 28% at times with terrible effects on my yields i tried using an ultrasonic humidifier but it only raised it by 2%. does anybody know of a more industrial cost effective way to raise humidity. i am considering greenhouse misters at the moment but worried it might affect my electrics. anybody out there with similar problems? help help help
  2. Not similar problems m8 but my tent runs as low as 15% with no effects, are you sure its the RH causing the problems?
  3. Yea I never had problems with a rH range of 15% - 70% lower towards flower finish. IMO 50% rH 24/7

    If you gotta add moisture small fan blow'in on water cheapest, or like me spill shit all over the place and make a huge fuckin' mess. Watch out for moisture on outside windows :talking
  4. low yields

    aha maybe tis not the low humidity that affects my yield. is there anybody out there getting killer yields with an RH of less than 45%?
  5. adam


    i have the opposite promblem and have to run a dehumidifier at 40%. lost a crop once to pm wont let it happen again:rain
  6. Zoolander

    Zoolander Premium Member Supporter

    I've had my RH at 30 % for flower and yield was great
  7. In low humidity (dry air) Leaves form narrower to reduce transpiration (natural evaporation), Leaves will be broader in a higher humidity space, increasing leaf surface area and trichomes, and so weight of manicured bud.

    I always believed that the battle is having as high a humidity as possible, making the leaves breath as efficiently as possible, too high will cause mold issues though.
  8. You will lose moisture if the room is too hot, increasing your ventilation may increase your humidity, as cooler air holds more moisture.

    If temperature isnt a concern then keep piling open containers of water into the room.:smoke
  9. In general, plants love humidity but they can do OK in low humidity too provided that they are healthy and past the seedling stage. During times of plant stress like botched transplanting and other grower screwups, it may be advantageous to raise your humidity, especially if its below 40%.

    The ultrasonics are the best and quickest. Dont get a bigger unit. You must seal up the room you are trying to humidify really good or the humidity will escape to less humid areas. That is for sure the reason it doesnt seem to be working for you.
  10. I've found buckets of water in the room don't help, maybe a wet towel hanging in there will be a better way to raise RH.
  11. satty


    I had the very same problem when i grew out some fantastic S.T. X Haze X S.T. My humidity was at 26%
    and my buds were very airy and at the time it was -23C.
    Tough growing situations for sure.
  12. Not true.
    We gotta X-plain that some more...

    "Because moisture (water vapor) is part of air (mainly nitrogen and oxygen, with other trace gases including water vapor), I hesitate to say that “air” has any temperature-dependent “capacity” or ability to “hold” water vapor. What I can say is that water molecules are constantly changing phases (solid, liquid and gas) and that the rate of change is temperature dependent (there are other factors involved as well). When there is more energy available (higher temperature), there is a net evaporation (more molecules evaporate than condense). When temperature decreases, there is a net condensation.

    So in the case of cloud formation, it isn’t that rising air cools and has less “holding capacity” for moisture, but rather that in a colder environment, there is net condensation, allowing for the growth of cloud droplets or even ice crystals."
    this dude said it

    On topic 'tino I don't think humidity is your culprit. Please take a picture of a leaf and post it...:nerd
  13. low humidity causing low yield?

    hey thanx for all the replies i will indeed try and post some pix soon. the temperature in the room occasionally
    reaches 28c so i am busy trying to increase ventilation to get it down to 25c on average. interesting to see that zoo has had good yields in low humidity. my previous grow was in a humid sub tropcal environment and i struggled to keep the RH down to 70% i had a lot of hassles with bud mould but i had two harvests that werent affected by it at all in the beginning. the first harvest was 2.1kg and the second 2.3kg if you consider that the light source was was four 400w hps then it was really quite high i all the while suspected that these bountiful harvests were the result of the high humidity! time will tell!
  14. julsbagell

    julsbagell Premium Member Supporter

    Heat affects yield, I wish I could keep my humidity at 30 percent in flower its got to be something else.
  15. low humidity not the culprit

    just to conclude: it seems that my reduced yields were from the ph of my organic tea being too low. i have now gone back to using bio bloom instead and everything is looking great... thanx for all the advice y'all!