Hi there oh Knowledgeable Ones,I need your advice.
My lights went off today as a result of an electrical failure,which I hadn't noticed.They had been off for 3 hours and when I checked the temp it was just under 60 F.(flowering room is outside by the way)
This was in the middle of the day as my lights are on from 9am to 9pm. This got me worrying about what the temperature is in there,at night during the plants dark period.
This would not have been a problem during the summer as the ambient temps at night were quite warm.However we are now coming into autumn(fall)and night temps are dropping.

I was wondering if I could safely(from the plants point of view)flip the 12/12 cycle on it's head and put my lights on at night?
Obviously I can't give them 24 hours of light and then start 12 dark 12 light again for fear of the dreaded hermies.
But can I safely give them 24 hours of darkness and then start 12 light 12 dark or should I gradually change it.
They are coming on really well in flower and I don't want to screw it up now with only 38 to 40 days till they finish.
Any advice would be great and much appreciated.

Thanks,Tumnus.

An extended dark period is not a problem but those
low temps are/will be. 60F is too cold. Night must be
frosty in there with them.

You are perfectly safe leaving them in a 24 hour dark period in order to change your light cycle from day to night.

Done this to many grows I've come to help out on where a patient has crazy high daytime temps running there lights at day in summer. If they go much longer than that (2-3 days) they can start stretching.

Ya Bro I Agree With What Has Been Said, Long Like Period Is The Way To Go To Change The Light Cycle..But Hey If You Just Have 40 More Day's???I Think If They Were Left Where They Are Would Be Fine For This Crop, Then You Can Change Over For The Next Grow.. You Need To Fix What Ever Is Flipping The Breaker???, Or Fix What Ever The Malfunction Was, That Could Really Screw Thing's Up.

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Cheers guys,got a much better idea of how to move forward now,thanks to you.I think night time lights is the way I'll go in autumn/winter and with mylar lining my shed,it shouldn't give off a heat signature like a cruise missile. May even put a small heater in there during the day,so the ladies are a bit more comfortable.
Solved the electric problem too,Hatch,bad earth in a pre fitted plug on one of my fans,so I cut the plug off and fitted one myself.
Thanks again for the invaluable advice.

Cheers,Tumnus.