I have a question about lighting

Here goes. First grow here and I found I have to switch my 12/12 to a nightime schedule. Currently its running 8am to 8pm.
Well the pool just got filled for the season and I don't have the power to run both the pool and my grow box, off the same circut. Besides it starting to get warmer here and night temps will help with heat issues also. My thought would be today about 3 pm shut the lights off. Then start again at 9 pm and run 12/12. I made it 9pm so I have an hr or two of light in am to inspect and prune etc. My plants are in 4 and 5 weeks flower. Anyone have any ideas on how the best way to do this. I sure would like to hear. This is first time ever for me and the plants look like a million.
https://www.rollitup.org/grow-journals/524437-1st-ever-grow-1st-ever.html#post7367997

great job on your first grow man. +rep for the green thumb

ideally you would want to change the time 1 hour a day but sounds like you need to do it a little faster than that. always give your plants more dark cycle when changing times. don't give them extra hours in light cycle. i would change them 4 hours a day for the next 3 days. so, when the lights go off tonight, change the timer for the lights to come on at noon tomorrow. then when you wake up the next day change the lights to come on at 4pm the next day and so on till you get to 9pm. the longer period of time you can stretch it over the less stress you place on the plants. if you have a week or so then maybe do 2 hours a day. that would be my suggestion. doing it all at once will not kill your plants but i have heard it can stress them enough to prolong flowering and affect yield. good luck.

That far along into flower you would possibly shock them into hermies. At the very least you would stunt budding for a week and you would notice some weird growth patterns. You gotta do what ya gotta do though in the end. I had the same problem at my last place and I just ran an extension cord to a rarely used outlet with a circuit that always had minimal load. You could always run a heavy duty outdoor extension cord to another source of power besides the one that your garden is using. That is what I would be doing if it was me since that would guarantee you not having to change your light cycle in the middle of flower.

yeah thats a tough spot..... if I had to do it Id do it like Nuglets suggested.....next time have the lights run over night... its cheaper and helps with heat!

Scared me when he said hermies. So after some thought, Im going to run a 110 outlet off the breaker box for the spa. run the spa and pool pump off one 60 amp circut. POOL IS SMALL AND PUMP ONLY 1 HP. That leaves the outbuilding on a 60 amp by itself. Little bit of work, I also found a reason not to run at night, I have a big street light up in my backyard, and it is on the outbuilding circut. My grow alone is pulling alot of power 4 fans, 1 air conditioner, 600 watt hps. I have 60 amps in that building, but it seems like the light dims a little when air kicks on. Thanks for the replies, I will be installing my 110 outlet for pool tomorrow. Unless a better idea comes up first.