Light cycle change - Please diagnose pictures! Sad plants.

Hey Peeps,

I need a diagnosis of what could be going on with these ladies. I hope you will be able to tell me by looking at these pics and hearing some recent activities.
The most recent change made to the tent was cutting back on light. They have been in veg for almost 5 weeks and have been holding up well. Four days ago, I decided to cut back on light, was 24 hours on then I changed it to 19/5. Well, they didnt like it too much as it got a little cold (prob mid 40's) in there, I let it go one more night on 19/5. The next day they looked a little better, but not much. Well I decided to get a space heater last night and set it at 55 and this is the outcome. Almost as if they were doing better without the heat but the cold would have probably done the same thing. Tonight, I switched back to 24 on, and hoping to put them in the flower tent tomorrow night. Lights off during the day, so no heater will be required.


Seem droopy, but water schedule hasnt changed much.

Some leaves are not as soft as others and some slightly cupped.


All this happened after adding the dark cycle. Prior to adding dark cycle, plants suffered a little heat stress when I was out of town. But it seemed like they recovered from that before I added dark.

I also need suggestions on how to transition to flower and what problems I may have when encountering the dark cycle.

First Grow

Your gonna stress them out by changing light schedule so much. I would pick a light schedule (18/6 recommended for veg.) and stick with it for a week or 2 untill the plants stabilize, then switch them to 12.12. Stress will lead to hermies and males.

run 24 hr on until you goto flower then just switch straight to 12/12.

your plants are probably just shocked, give them a few days(Not half assed, lights constantly switching, temps flying all fucking over, few days. But normal consistent days) they should be just fine.

john pickle said:

run 24 hr on until you goto flower then just switch straight to 12/12.

your plants are probably just shocked, give them a few days(Not half assed, lights constantly switching, temps flying all fucking over, few days. But normal consistent days) they should be just fine.

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Thanks John, I was planning on going back to 24 hours for a day, but I will wait till they look healthy enough to transfer. I figured it was intense stress (heat, cold, and light) from the past couple weeks.

Can't believe that nobody else had input.

I am not a fan of 24/0 anyway. I have had better overall success by doing 18/6 and then straight into 12/12 when ready. I tend to think the temps are as much to blame as the light cycle changes are. I would stabilize them on 18/6 and then straight into 12/12 when they have perked back up.

Little Tommy said:

I am not a fan of 24/0 anyway. I have had better overall success by doing 18/6 and then straight into 12/12 when ready. I tend to think the temps are as much to blame as the light cycle changes are. I would stabilize them on 18/6 and then straight into 12/12 when they have perked back up.

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My problems came from moving from 24/0 to 18/6. Was it a temp or humidity problem? I already switched back to 24/0 and plan on keeping it like this till they get healthy, then straight to 12/12 with lights out during the day to better regulate temps.

Actually I think your stress came from zero darkness to 5 hours of darkness. These plants don't know dark so yes, its more of a shock than if you were running 18/6, like nature.
Another benefit to 18/6 is the plants are used to cooling in the dark cycle a few degrees, like nature. So dropping another 6 hours of daylight and heat when we switch from 18/6 to 12/12 is something they are predisposed to do, like nature.
If you run 24/0 all the time the plants have very little tolerance for temp fluctuation. That will cause them to stretch and potentially hermie if they gets pissed off enough.

How bad was the heat stress? A couple degrees or were they flopped over like wet noodles?
How long between stress and introducing light?

Just thoughts brother,
good luck

medimaker said:

Actually I think your stress came from zero darkness to 5 hours of darkness. These plants don't know dark so yes, its more of a shock than if you were running 18/6, like nature.
Another benefit to 18/6 is the plants are used to cooling in the dark cycle a few degrees, like nature. So dropping another 6 hours of daylight and heat when we switch from 18/6 to 12/12 is something they are predisposed to do, like nature.
If you run 24/0 all the time the plants have very little tolerance for temp fluctuation. That will cause them to stretch and potentially hermie if they gets pissed off enough.

How bad was the heat stress? A couple degrees or were they flopped over like wet noodles?
How long between stress and introducing light?

Just thoughts brother,
good luck

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Did you miss the part where he said the temps got down to mid 40's during his newly introduced dark cycle? They really shouldnt get too stressed from just a little light change like that. But the stress induced from the TEMP fluctuation was definitely the bigger factor in their sadness(because, you know, it was bouncing around with a range of 30-40 degrees).

Regardless... you have a heater now, and they should be fine.
good luck, grow some good bud

john pickle said:

run 24 hr on until you goto flower then just switch straight to 12/12.

your plants are probably just shocked, give them a few days(Not half assed, lights constantly switching, temps flying all fucking over, few days. But normal consistent days) they should be just fine.

Click to expand...

It was definitely temp and light stress. Looking a lot better today after getting back to a normal and consistent schedule. I'll give them another day. Thanks jp