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Plants Start Drooping Toward Night Time

Discussion in 'Hydroponics' started by ArmedGeek, Jun 3, 2017.

  1. I'm running 18/6 veg light. Three weeks in veg (about the time they started stinking) i have noticed three hours prior to night, the plants start drooping. When this occurs, they look extremely pitiful and sad, very sad.

    It just started happening the last couple days and temps/rh have been the same since week 1 of veg. However when the plants wake up, they look extremely healthy and perk right up.

    There are many threads regarding this topic, but i have yet to find the exact reason why. My natural thoughts are this is normal, as the plants have learned the light cycle. Around three hours prior to drooping, they are exhausted from the days light, and are literally getting ready for night time.

    I could use some expert opinions on this topic. I have thought about changing my light cycle to 16/8.

    RH 46-58%
    PH 5.8 (rarely any swings but adjusted within hours)
    600w LED 28" away from canopy
    Temps 73 f night 76-78 f day
    Fans running over canopy.
  2. Smerb


    With humidity at those levels the moisture in the air will make your girls sag at night. Does your fan go left to right over your canopy? Or is it constantly blown on plants? Touch your leaves and feel if they are cold or hot, or if they feel moist. Check everything, stir your pots up to let airflow. All the little things. Pictures will help.
    ArmedGeek and jipp like this.
  3. The girls tend to be drooping and sad looking a couple hours prior to night. During night, i can't see what they are doing but when lights come back on, their healthy looking and have perked up. I don't believe night is the issue. I can't seem to figure out what's going on those few hours right before they go to sleep while the light is still on.

    To answer your questions, i don't have the fan circulating at this time and its pointed side ways toward my tent. However, it's a 16" hurricane and is too strong to start circulating. On low, the leaves/plants still experience subtle air movement and sway but the air is gently but constantly hitting them at all times. The leaves are slightly moist to the touch and a little cold.
    Smerb likes this.
  4. Smerb


    When they are about to take a nap the environment plays the whole role. The leaves being cold hinders transpiration, plants sag when to moist, to dry, and also when they meet more root space...
  5. Veg thrives between 50-70 rh. However, it is totally dependant on the type of strain being grown. Some indica prefer dryer climate in comparison to other sativa strains simply because of the environment their originally from. I see what your saying, but I wouldn't consider leaves being kind of cool to the touch to cold with 78f temps. This is actually much higher than I like. Also, being that I'm in bubblers I'm not root bound.

    I do however agree that over watering/root bound would contribute to droopy leaves in a Coco/soil grow medium. With that said, I would expect droopy leaves the whole time if over watered until dried out, or until transplanting due to root bound. My rh and temps are within range, I don't top feed and I'm dwc.

    This has to be part of a plants life cycle in terms of the growth cycle. I'm just trying to understand what's actually happening in technical terms for a complete understanding to broaden my knowledge.
    Last edited: Jun 3, 2017
    Smerb likes this.
  6. Smerb


    I can send more info about blowing air across your plants. If everything is on point this tad bit of info is important just as all the other info,Haha.
    ArmedGeek likes this.
  7. Smerb


    It may be 78 but the leaves may be 68 or less.
  8. lol hey this is true
    This is true, i've had a hard time finding the optimal distance from the canopy to the light. For most LEDs people say 24" but there are many different types of LED technologies and there simply isn't a one fits all solution. I'm more of a rule of thumb kind of guy. Thanks for your input, at least someone is responding.
  9. I found the below information in a different forum. I asked for technical, but this might be too technical =]

    The exchange of oxygen and carbon dioxide in the leaf (as well as the loss of water vapor in transpiration) occurs through pores called stomata (singular = stoma).

    Normally stomata open when the light strikes the leaf in the morning and close during the night. The immediate case is a change in the turgor of the guard cells. The inner wall of each guard cell is thick and elastic. When turgor develops within the two guard cells flanking each stoma, the thin outer walls bulge out and force the inner walls into a crescent shape. This opens the stoma. When the guard cells lose turgor, the elastic inner walls regain their original shape and the stoma closes.

    Time Osmotic Pressure, lb/in2
    7 am 212
    11 am 456
    5 pm 272
    12 midnight 191

    The table shows the osmotic pressure measured at different times of the day in typical guard cells. The osmotic pressure within the other cells of the lower epidermis remained constant at 150 lb/in2. When the osmotic pressure of the guard cells became greater than that of the surrounding cells, the stomata opened. in the evening, when the osmotic pressure of the guard cells dropped to nearly that of the surrounding cells, the stomata closed.
    jumpincactus likes this.
  10. I bet i would feel droopy too after being awake for 18 hours and doing nothing but growing. The top post in comparison to what i'm seeing makes total sense, because i do see the actual stomata closing up prior to lights off. In my case, the leaves droop also in which must be a normal activity. Those who argue this isn't a normal, simply might not notice the change as much as it is strain/genetic dependent. They all do it, some just show more visual signs to the eye than others. I really am a geek :\
  11. I currently have a couple outdoors (in the ground) and I experience the same thing. Once the sun is on the horizon I tend to notice the droop. In the morning they look perky and happy. I water manually and their last watering comes around 430 everyday.
    Madmax and ArmedGeek like this.
  12. Also low temp is not an issue for me, as I'm in southern Az
    PharmHand and ArmedGeek like this.
  13. Thanks dannyk, I appreciate the input man.... (or woman =] ). No sexism here dog.
    No seriously, it's good to know that someone is experiencing the same thing, even though it's in a different atmosphere and grow status.
    PharmHand likes this.
  14. Your plants are just going to sleep. Mine always droop in Veg and hour before lights out
  15. PharmHand


    Mine do it in veg sometimes too. There's something called the daily light integral, it has to do with the amount of light intensity and duration a plant receives in a 24 period. It's usually recommended ( by lighting companies like gavita)that you veg with less intensity than flowering because the plant is typically receiving 50% or more hours of light per day 18vs 12. This is because a plant can only process so much intense light in a day. In nature a plant would NEVER receive 18 hours of intense light in a day.

    When your plants droop like that the stomata are mostly closed which means it's not photosynthesizing efficiently maybe even photorespiring which actually wastes energy. I would bet if you or @CaliRooted were to dim your lights or reduce intensity for the entire 18 hour period your plants would stay perky for the whole lights on period.

    Guys like jungle boys have realized this so to save electricity they'll veg for 12 hours intense light and 6 not so intense. I used to work at a coop where the rooms were on 12 hour flip flops, when our veg room was full we'd veg in the flower rooms 12 hours intense 6 hours overhead fluorescents and the plants grew just as fast as the veg room plants. You'll hear guys say that you can veg under 24 light and you can but try doing it with intense light and you'll end up w some sick looking droopy plants....... I'm a geek too bro:eyepiece:
  16. Sounds like sleep deprivation, I hate sleep deprivation
  17. Morning from the uk bud. When you moved them to flower, were they under sodium lights? Did you find that promoted closer interrnode spacing?
  18. PharmHand


    A good HPS bulb will promote rapid growth and ,if plants are spaced right, will promote a lot of lateral growth. Tight internodal spacing can be achieved w HPS if plants are adequately spaced. In cramped conditions a bluer spectrum can be helpful to control height
    1diesel1 likes this.
  19. (Not trying to take over your thread just trying to give a side tip/ anther viewpoint )
    I run my lights at dj shorts lights cycle suggestions rate.( if you didn’t know who dj short is he is famous for blueberry strain )

    Veg: 17 hr on 7 hr off
    Flower: 11 on / 13 off

    Overall I’ve ran two runs and the plants seems less stressed, betters flavors/terp % and the obvious look at the electricity savings (if you think 2hrs everyday x whole grow season , def adds up if the plants aren’t showing dramatic effects in the negative )

    To test your plants “happiness “ of distance of a led, par meter the distance and see after you did any modifications in 12 hours if the plants if the leafs are “upward” , and it’s always good to have a temp/humidity probe on top of your conopy and reset it everyday and see what your max is. Once I started measuring my canopy and par metering them and making sure my temps would never be off. My issues disappeared ( I use cob’s and spydrx plus ) simple but a huge mistake soo many growers fuck up on
    Last edited: Dec 7, 2018
  20. ethcan


    Not sure why people are suggesting there is anything wrong with your plants.

    It is 100% normal for them to droop near the end of the "day" portion of the photoperiod, as they begin to shut down and prepare to go into processing mode through the "night" portion of the photoperiod.
    Bulldog420 likes this.