Changing light schedual

Hey guys I have my light on now mostly durring the day at 12-12 already. its the first week of tht and the plant is 8-12" tall topped once. I want to switch the 12-12 to be at night time only as thats when it gets cold in the basement and i think the lights on would help keep it warmer at night as durring the day the furnace is running more often and it pretty warm down there.

Im using a 320w MH coated bulb/reflector and about 300w of t-5's for side lighting.

What is the best way to shift the time the light switch on/off without stressing the plant as of now they turn on at about 8am and obviously off at 8pm.

I have read that when changing a light schedule it is best to "change the light cycle by 15 minutes every 24 hours"... now I've also read that "plants only measure darkness, so if you need to make adjustments to your timings, make the days longer/shorter to compensate, whilst always maintaining 12 hours of darkness." Hope this gives some explanation.

Just let them stay dark until the time you want them to come on again. If they go off at 8:00pm let them stay dark until 8:00 pm the next night, then turn 'em on and go from there. Do not violate that dark period, tho.

sounds good. so for one day if they get 24hrs of dark thats ok? i should just wait till the night and then set that as my start time?

Yep! They wouldn't handle the daylight for 24 hrs, but I've done what you want to do several times over the years, no problems.

how big did you start to flower your plants as 8-10" is not very big, what are you expecting yeild size to be ?

not much yield expected this was just a random seed on my female plants from outdoor harvest. hopefully an oz just to buy some new games this holiday seaason. i FIM'ed it not topped and it has 3 new main stalks

oh right okay GL Bro