plants start drooping towards the end of the day

apbx720 said:

ive got an indoor grow tent(5'x5'x7'). using 1000w hps 3.5 feet away. plants are 3 weeks old. an AC unit keeps the temp from 70-75F with rh between 40-50%. ph is 5.6-6.0. top feed drip w 40gal res watering 4 times a day for 30 min each watering. hydroton clay pellets. 18/6 lighting. using 1/4 strength AN nutes.

Ive noticed that my plants all start to droop as if they get tired at the end of the day. ive played w water schedule, temp, rh, nutes, ph, flushed, none of which affected the drooping. they usually start drooping at around 5pm and by 10pm , when lights go out, they dont look too good, sometimes the bottom leaves touch the ground. the plants seem to otherwise be doing good. theyre still growing fast but they just dont look happy and vibrant like they do in the morning. is it normal for plants to get "tired" as the day goes on? is there something i need to do to correct this or is it not really something that should concern me? i can post pics if anyone needs me to. thx in advance for any comments.

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yankeetransplant said:

I agree...perfectly normal....circadian rhythms occur with MANY living organisms....Including humans....So many want to think its problems related to SOMETHING else....
I had a friend so intrigued with it, he started looking at how sativa strains differ from indica, AND hybrids when it comes to it....He said his researched showed that it occured more so with Indica strains due to their origins...Indicas are indigenous to very northern (and southern) latitudes....They veg under VERY long days and flower faster when the days shorten, to reproduce before winter and cold kills them....Sativas photo cycles can vary by a mear hour or 2 (in nature) btwn summer and winter solstices....Of course, this is why equitorial sativas can take 15-16 weeks to flower, and sometimes never do it completely before they want to 'veg' again....MINIMAL changes effect what they will do.....Sativas just dont react as fast as indicas with photocycles...It is EASY to get indicas (and many hybrids) to adapt to a specific growers enviromental parameters.....Such as the cuttings I have obtained that were vegged under 18 hours that ORIGINALLY were wilting after 18 hours of light, and ultimately stopping that once they adapted to my 24 veg cycle....Dont want to beat this to death with my experiences, but I personally find it amazing how they DO adapt to specific enviroments......I'm surprised there are not any IN-DEPTH studies about it in the cannabis industry....Maybe cause there is nothing major to gain from it except being interesting....YT

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• Diurnal (night and day)
• Circadian (24 hours)
• Ultradian (less than 24 hours)
• Infradian/Circalunar (1 month)
• Circannual (1 year)

TeW33zy said:

I am a Sr. Biosystems Engineer, Algriculture with masters in M.S Medical Technology and I've read the responses and I'm quiet shocked at the responses of which they are incorrect, that is not what's going on. If your plant dropps during the day it's either A (underwater) B (overwatered and no oxygen in the roots) C (light stress). If the plant droops hours before bedtime it's C (light stress). Your plants are extremely tired and can no longer photosynthesis. They are on 18 hours a day and cannabis plants can only photosynthesis so much light in its daytime period. Through a process called phototropism they are creating their own organic nutrition usinh light, magnesium and CO2 to do this. If she gets tired say 2 hours before bed then raise the light. 25 umols/ms =1 hour rest. So decrease your ppfd by 25 umols and wait 48-72 hours. If they droop 1 hour before bed reduce by another 25 umols and check 48 hours later. It should no longer droop before bed. If she still droops then there's problems in the roots or you need to drop your ppfd by 25 until they don't droop. However it depends on the age and your ppfd. If you are way to high of ppfd by say 400 then just do it the first time. Ppfd should be 160 then 200 then 250 thrn 50 umols each week addition. It requires knowledge in what your doing. You guys joined a game you know nothing about as far as Algriculture and diagnostic issues. Growing cannabis is a "follow a recipe" but when u have problems you don't know nothing because you never went to school for Algriculture.

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TeW33zy said:

I also read the guy below say drooping is normal and it's called "Circadian Rhythm" and it's perfectly normal. Well where did he get his Masters Degree in Algriculture because he has no clue what he is talking about. First off, That's not the correct term, that's the output of y=f(x) where y is the output, f is the function and x is the variable. The function is the light and variable are biological responses to growth. The process instead is called Biological Rythms and there are 4 which are:

• Diurnal (night and day)
• Circadian (24 hours)
• Ultradian (less than 24 hours)
• Infradian/Circalunar (1 month)
• Circannual (1 year)

This has 0 to do with drooping.

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