do leaves droop when its too cold

im trying to figure out why my leaves droop. ive ruled out heat stress but now im thinking it could be the opposite. its getting down to 60-65 at nite and usually 85 durring the day but the daytime temp has dropped to around 75.. if u can answer thanks alot!

Just curious - is the droop more pronounced at a certain time in their light schedule (like when the lights first come on or just before the lights normally go out)?

they were fine when i turned the lights on.. then they started to droop. i also turn the fan on at the same time i turn the lights on. i turned the fan off and about 10 minutes later the leaves were sticking straight out.. maybe the fan is too strong. have u ever heard of that? too much circulation. thanks for helping. +rep.

It's actually a complicated subject due to so many possible causes to leaf droopiness and it also doesn't sound severe (and could be a perfectly acceptable plant response). But just for the hell of it, here's two rules of thumb one can use in troubleshooting - just have to differentiate the drooping being caused by the leaf stem or if the leaf itself is curling or drooping:

"Leaf angle is controlled by the hydration of the petiole, as affected by soil water content, atmospheric vapor pressure, and air temperature."

-- Or in other words, if the leaf stem is actually the cause of the leaf moving downwards suspect over/under watering, humidity, wind and/or temperature.

"In contrast, leaf curling is a specific response to leaf temperature, and bulk leaf hydration has little effect."

-- Or in other words, if the leaf itself is curling suspect heat/cold stress.

You can probably rule out most of the other causes of leaf drooping considering you can observe a rapid stimulus-response.


---------------------

Just to add, and make it more complicated, plants also have strong circadian rhythms that are tied into transpiration rates (which is in turn tied into humidity and wind) that occurs in leaves (along with photosynthetic processes) and will result in drooping and perking up according to their biological clocks and the fact that daytime tends to see more wind movement. So you will often see cannabis leaves start to droop as it gets close to when that rhythm signals them that the sun is about to set or perk up as it is about to rise.

I know that's probably too much info, but it's interesting shit.

rsharp said:

im trying to figure out why my leaves droop. ive ruled out heat stress but now im thinking it could be the opposite. its getting down to 60-65 at nite and usually 85 durring the day but the daytime temp has dropped to around 75.. if u can answer thanks alot!

Click to expand...

your roots are probably not getting enough oxygen. your temps should be fine. if your growing in soil, water less often. if hydro, add some air stones.

it is very common for leaves to droop if there is not enough water, but im sure you ruled that out. however over watering has the same symptoms as under watering. roots actually need oxygen. kinda like fish in a fish tank. they will die eventually if you dont have a bubbler.

The leaves will droop when it is cooler and dark, that's just natural for any plant.

they usually change colors from the cold not droop. let it dry out and get some air.

you all have great answers. i think i pin pointed what was wrong. i think the main problem was too much circulation. that cold air passing through real quick. it was drying my soil out extra fast plus causing cold air temps. what i did was turn the fan on low and restricted the air flow. temps went up and the plants perked right up. they look awsome today!!!! THANKS AGAIN!!!