Changing up light schedule during flowering?

BIG QUESTION: is there a way to change my light schedule while already in flower? If so what's the best way? Extended darkness, or extended lights on to get me to the schedule I want. Add an hour of light and dark till eventually I get to where I want to be and then go back to 12/12?

I flipped my ladies to 12/12 about 10 days ago, they've already started flowering. I was wondering....... Lights are on from 11am to 11pm, now 10 to 10 with the time change. Now I'd like to run my lights from like 8 pm to 8am. That way I get off peak usage hours and I don't have to use electricity for a heater at night. With the lights on the flower room stays 6-8 degreesF above the temp in my lung room. Changing the light schedule would allow the lung room to get to 58 degrees at night while maintaining 64-66 in the flower room without my heater having to work.......

Is it possible to change my schedule without stressing the ladies, or am I stuck at this schedule for now? Please,anyone who knows what's up with this, fill me in.

Just opinion, if your ladies are autoflowering, then it shouldn't make any difference. If they are not autos, then scaling them back could herm them out, or make them revert to veg. It might not, so the less you shock them, then the less likely they will change up on you. So if you're going to do it, I'd extend the dark first, then the light. That way you're not going to get them more than 12 hours of light per day. Getting more than 12 hours of dark is okay, but getting more than 12 hours of light can re-veg your girls. As long as you don't interrupt the dark cycle you shouldn't have problems. Just opinion.

The safest way to do it to ensure that you don't stress your plants at all would be to go 12/13 until you reach 8 pm to 8 am and then you can go back to 12/12.
Mapped out it would look like this:
(- = lights on) (~= lights off)
Day 1: 10 - 22 ~
Day 2:~11 - 23 ~
Day 3: ~12 -
Day 4: -00~13 -
Day 5: -1~14 -
Day 6: -2~15-
Day 7: -3~16-
Day 8: -4~17-
Day 9: -5~18-
Day 10: -6~19-
Day 11: -7~20-
Day 12:-8~20

By doing that you're missing out on 12 hours of light, an hour each day. If you want a more direct route you could probably do
Day 1: 10 - 22~
Day 2: ~20-
Day 3: -8~20

That'd put your lady in the dark for 22 hours which would likely cause some stress but I'd like to think that shouldn't be enough to herm your plant. I don't have experience switching so drastically like you want to but logically these make the most sense to me. No risk of revegging and minimal risk of stress that could cause herming, all for the trade-off of less light for a 3-12 days. Just play around with the numbers and find whichever way seems best to you, maybe you can think of a way that makes more sense than these two.

Extend the dark period once. Simply don't mess with the light schedule for more days than needed.

Warble, Bryleetch, thanks guys. I appreciate your time. They are clones not autos. So never extend the lights on period in flower period. 12 hours of light no more. It is a drastic change I want, probably the thing I planned least for as I thought most everything out an awful lot. So If I did 12/13 it'd take 12 days to get to where I want to be. That puts me 22 days into flower out of 56-60 days of flowering. Which has me at my ideal light schedule a month before harvest. Meanwhile it is getting colder, the heater may fall short of keeping up the temps on it's own in the dead of winter, it may need the help of the lights to keep the temps up, maybe not. Damn........ i do loose a full 12 hours of light in that time too.

Sativied, so you think if I leave the lights off from 10 tonight to 8 tomorrow night will be fine. 22 hours of darkness to get me to where I wanna be. May stress them but not herm?

Sorry Sativied obviously that is what you think, as you took the time to write it. I'm gonna do that, lights out tonight till tomorrow night. I'll keep an eye on everything and look for any signs if herming.

Obviously the best thing is to not change, but if you really want to, do it over a short period instead of spreading it out over two weeks or so. A shorter dark period is what you should want to avoid, a longer day is not really an option either (although it wouldn't start reveg within a day). Which means you either have to run a longer night, or shorter days, for example you could run 8 hrs light and 12 hours dark till you get to the point where you are. The plant will re-regulate and adapt over a couple of days, might as well get it over with as fast as possible.

I obviously can't predict if they will or won't herm but let me put it this way, I'd be more worried about stressing them too much if I were to change the photoperiod for several weeks than for a day or two.

It's way easier that way, with my intermatic timer I would have to constantly be changer the trippers, throughout the transition using 12/13.

Well after the thought of risking herm. Hell no. I haven't cut any corners yet. I spent a lot of cash to build my grow environment and have 7 weeks into these first 4 plants that I have ever grown. No way am I going to risk herming them out. That'd be stupid to end up with a shitty harvest after all this time, money and effort. I'd rather spend the $ on electricity, I have the amperage, even get another heater for the last few weeks of this grow if it becomes necessary. Simply not worth the risk. Thanks again for the help guy's.

extended dark, or up to 24 hours of light during flower is not enough to shock them into craziness. best is extended dark, but either or, tomato/tomato, it'll be fine. sativied is spot on. you will stress out more than the plants, and you are more likely to herm than the plants...

you can run 14/10 or 11/13. you can flip from 12/12 to 13/11 or 14/ 10 week3 and back last 2 weeks or keep it the same.

You want to run 730nm Infrared led's for 5 - 10 min after light turn off. Mimicing sunset sending the plant into its phytochrome state faster (within minutes) as if it were outside. Without IR at lights out it takes 2 hours for the plant to go into its pfr state and the plant needs a minimun of 10 hours of pfr sleep. You also need 660nm deep red at lights on to bring the plant out of pfr state.

Joven Agricultor said:

Sativied, so you think if I leave the lights off from 10 tonight to 8 tomorrow night will be fine. 22 hours of darkness to get me to where I wanna be. May stress them but not herm?

Click to expand...

nearly no stress, and no herm (not due to the darkness anyway). if they're prone to herm genetically, the extended one-time darkness will make little to no difference.

Constant state of learning, I love marijuana and I love the RIU forums!

lol i just did this same exact thing. I was running 11pm to 11 am. Just at 11 pm last night, i changed the grow to 8am - 8pm. just let them have another 9 hours of dark.

I've experimented with alot of extra dark/crazy light schedules just for science etc... I've put some plants through up to 10 days of total darkness and I've only experienced one herm from it. I have also "tortured" individual plants with all sorts of insane light schedules/temp changes, for experimental purposes, and have only had one plant herm from it. Several times I've created a Frankenbud by revegging/cloning a big bud, and putting it in a very sunny location during the summer for 1 week at a time , Then darkness 16 hrs a day for a week, repeating over and over. It creates a basketball size and shape bud/plant that puts out single and double pointed leaves from within the bud that I just trim off as they show. I did have a Maui Waui Frankenbud that eventually kicked out 6 seeds that all grew vigorously and were all ladies... Just my experience so far.

Just extend the dark period until you are ready for the lights to come back on. I did this last year and honestly the plants LOVED the extended dark period. Everything will be fine

Its worth mentioning that off peak power does not really work that way.
There is a separate circuit and meter for off peak usage in your homes electricity box.
Generally only hot water is connected too the off-peak circuit and meter.
The power company sends a signal that triggers the hot water heater to turn on.
At least its this way in Australia, pretty sure most of the rest of the world ....

Change the lights once using extended darkness. I do this every year, once when summer comes to have lights on at night and reverse it during winter so lights are on during the day. Never had a problem. Problems happen when you keep messing with them. A one time extended darkness will not hurt a thing.

Sent from Northern Colorado.

I am doing this right now too. Went from lights being on during the day, to being on at night. I eased into it with 12 hours of light, and 17 hours of dark. After 3-4 days, went from 6am-6pm on, to 10pm-10am on. (I'm actually nearing the end of the process right now. I'll make the last change tomorrow). Haven't seen my girl in 3 days! Miss her. (Ha)