temperatures 101 ( In neeed of help )

Discussion in 'Advanced Growing Techniques' started by e3ment444, Sep 29, 2009.

  1. alright I have a 10 plants going from 12/12 from seed, my temps when the light is On is around 80-86,

    I know the Proper temp range is 75-79.

    but would this effect the flowering stage that much,
  2. Yeah mine tops off at 87-88 at times, even know it's my first grow and I'm waiting on seedlings you think it would affect there growth? I plan on upgrading my 80mm Antec Fans
  3. My grow box stays around 83 when the lights are on and can drop to 75 or so when theyre off and my plants are doing wonderful. I don't think that 86 is extreme enough to mess up your grow it may just stunt the growth. Thats just my 2 cents!
  4. I grew in an attic spaace and with the HPS itd get to low 90's and sometimes even a lil higher. That was def the point where you could see the plants were awfully pissed bout it. Didn't have huge issues though... just frequent watering and finicy plants. Anything in the 80' is just fine
  5. over 95 is bad.

    Proper temperature is one highly variable factor. Most books state optimum grow temperature to be 70-80 degrees, but many list extenuating circumstances that allow temperatures to go higher. Assuming genetics is not a factor, marijuana plants seem to be able to absorb more light at higher temps, perhaps up to 90 degrees. High light and CO2 levels could make this go as high as 95 degrees for increased marijuana growth speed.* An optimum of 95 degrees is new data that assumes very-high light, CO2 enrichment of 1500 ppm and good regular venting to keep humidity down. It is not clear if these temperature will reduce potency in flowers. It may be a good idea to reduce temperatures once flowering has started, to preserve potency, even if it does reduce growth speed. But higher temperatures will make plants grow vegetatively much faster, by exciting the plants metabolism, assuming the required levels of CO2 and light are available, and humidity is not allowed to get too high.
    With normal levels of CO2, in a well vented space, 90 degrees would seem to be the absolute max, while 85 may be closer to optimum, even with a great deal of light available. Do not let the room temperature get over 35 C (95 F) as this hurts growth. Optimal temperature is 27-30 C (80-86 F) if you have strong light with no CO2 enrichment. Less than 21 C (70 F) is too cold for good growth.
    Low temperatures at night are OK down to about 60 degrees outdoors, then start to effect the growth in a big way. Mid 50’s will cause mild shock and 40’s will kill your plants with repeated exposure. Keep your plants warm, especially the roots. Elevate pots if you think the ground is sucking the heat out of the roots. This is an issue if you have a slab or other type of cold floor.
    As temperature goes up, so does the ability of the air to hold water, thus reducing humidity, so a higher average temperature should reduce risk of fungus.
    Contrary to many reports, high humidity is not good for plants except during germination and rooting. Lower humidity levels help the plant transpire CO2 and reduce risk of molds during flowering.
    Studies indicate the potency of buds goes down as the temperature goes up, so it is important to see that the plants do not get too hot during flowering cycles. ? D. Gold: CO2, Temperature and Humidity, 1991 Edited by
    E. Rosenthal.

  6. awesome little read!!!

    and just how i like 'em: short and sweet.


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