Increasing lights off temperature to shorten node length

Discussion in 'Advanced Growing Techniques' started by lep-rechaun, Feb 26, 2023.

  1. I read somewhere that if the lights on temperature is much higher than lights off, the nodes length will increase. I'm using LED lights that raise my day time temp slightly to around 72, but the night time temps drop to around 67.

    So, I'm thinking of experimenting with a heater to raise the night time temps a few degrees higher than the day time temperatures, lets say around 72 Day temp and 74 night time.. Will this help keep the nodes shorter and my plants bushier?
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  2. more light will shorten internodal spacing. Blue light to be specific.
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  3. The process you're referring to is called DIF -

    Plants will respond rapidly to the day/night differential. Growth rates often escalate in as little as 24 hours after the temperature change. Large swings in the DIF produces rapid stem growth, but dramatic temperature changes also increase the humidity in the greenhouse or grow room. Nighttime humidity increases can cause mold or stunted growth in plants, so if a grower utilizes DIF to spur plant growth, then humidity levels must be controlled and maintained.
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  4. Gee: if I want to shorten internodal length I simply change my COLOR Temp from 2700K(kelvin) to 6500 K
    it makes a short squat plant that members here often avoid, for all that molds gonna build up inside the forth coming cola, guaranteed as the night temps are so low:
    so many go the opposite and make a slightly stretched plant
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  5. Thanks, I'll google DIF-- I didnt know there was as word for this.

    Humidity isn't an issue for me, I have a large dehumidifier that can easiy control RH. What I'm short on is grow space and my height limit is around 4 feet. ( I train all tops evenly using LST and manifolds to keep the plant really low....)

    Large swings in the DIF produces rapid stem growth, but dramatic temperature changes also increase the humidity in the greenhouse or grow room

    So, if the large swing in temperature is opposite the normal (obviously night time temps are cooler on average) will it keep the nodes shorter?
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  6. Good stuff, thanks this makes a lot of sense and the last thing I want is mold in my buds....

    For winter grows, my RH is so low ( 35-40) that I actually use a humidifier to increase RH during veg (around 50-55). But during flower I let the RH drop to 35-40 or so. Its pretty dry for me during flower and I doubt mold will form with such low RH. (correct me if I'm wrong)

    Anyway, I've grown the same strain 4 times now and am curious to see what effect a slighly higher nightime temp would have on node length.

    (Note:) I defoliate heavily leaving only the tops (Lollipop) with buds growing. I'm done with the lower buds, they just dont seem to be worth it to me as far as quality goes, so I only grow the top of the top and cut everything else off.... I wind up with 8- 30 tops (per plant) depending on my grow style and all are at even height getting equal light.
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  7. I'm using spiderfarmer lights, I dont think the light (color) temperature can be chaged. My plants are getting plenty of light though, in some cases too much.
  8. add VPD to your study list if you aren't familiar with that term too :)
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  9. i use the MH lights for veg the first few weeks the blue lights keeps them almost too tight you can try lowering your light a few inches so they arent REACHING
  10. Let me introduce you to Dr. Bugbee. :love-m3j:


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