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View Full Version : Changing Light Cycles 18/6 - 12/12???



Steptoe
20-06-09, 05:44 PM
Hi,

I have been vegging my plants for 4 weeks on 18/6 and now I want to switch them over to 12/12.

My lights currently come on at 9:00am and go off at 3:00am, so do I need to let the dark period go from 3:00am (lights off) to 15:00pm and then let the lights come on or should I let them come on at 9:00am (as normal) and go until 9:00pm?

Any help/advice would be much appreciated.

ash1983
20-06-09, 05:50 PM
I normally give my plants 24hr darkness to give them a bit of a kick start. Dont worry about it too much though just change light cycle to 12/12 when your ready.

wert
20-06-09, 05:58 PM
as ash says it is not as important in veg with a one off but if you are going to change your light schedule , extend the dark period not the lights on period as it is messing with the light on period that can cause stress.

Steptoe
20-06-09, 06:01 PM
Cheers Ash,

This is my first "normal" grow as I've only grown auto's before, and wasn't sure what would be the best way to do it.

Hi Wert,

So, I could just go (lights off) 3:00am (lights on) 15:00pm for 12/12 flowering then?

skunkmaster
20-06-09, 06:03 PM
i also give them 24 hours of darkness before kicking in the 12/12

Steptoe
20-06-09, 06:09 PM
Hi Skunk,

If I gave them 24 hours dark that would mean lights on at 3:00am and really I want lights on at 15:00pm, could I then, leave them 36 hours in darkness or would this be too long?

wert
20-06-09, 06:11 PM
Cheers Ash,

This is my first "normal" grow as I've only grown auto's before, and wasn't sure what would be the best way to do it.

Hi Wert,

So, I could just go (lights off) 3:00am (lights on) 15:00pm for 12/12 flowering then?

yes
......

skunkmaster
20-06-09, 06:11 PM
some growers do give them 36 hours without any concern

My Tent Or Yours
13-02-14, 12:10 PM
Hi, First timer here.

I`ve had my plants in the veg state since germination 6 to 8 weeks ago, I was told a 12/12 cycle! Now I know different...

Should I just immediately switch to a 16/18 hour cycle? Or do it gradually?

Any advice would be greatly appreciated :)

My Tent Or Yours
14-02-14, 09:48 AM
Any advice would be greatly appreciated :)

TheKraken
14-02-14, 09:59 AM
I would go with lights off from 8am to 8pm, lights off during the day will reduce the temp difference between the cycles. This is a good thing.

TheKraken
14-02-14, 10:01 AM
Any advice would be greatly appreciated :)

You will need to veg for a cycle of either 18 on 6 off or 24 on 0 off, then when you want to flower you should switch to 12 on 12 off or 13 on 11 off.

algie
14-02-14, 10:07 AM
because i have a perpetual grow my room is never empty, i take plant out of veg room lights on, i put them in the tent lights on, the lights go out in the tent for 12 hours, next day is day 1.

My Tent Or Yours
14-02-14, 05:56 PM
You will need to veg for a cycle of either 18 on 6 off or 24 on 0 off, then when you want to flower you should switch to 12 on 12 off or 13 on 11 off.

Thanks, Ive been vegging for 12/12 for the last 6/8 weeks. Shall I change immediately to your suggested cycle? Thanks again :)

TheKraken
16-02-14, 07:31 PM
Thanks, Ive been vegging for 12/12 for the last 6/8 weeks. Shall I change immediately to your suggested cycle? Thanks again :)

Indeed, a 12/12 cycle will induce flowering. A 13/11 cycle will give around 50-60 extra hours of light during flowering, something the plant would enjoy wholeheartedly.

Alzy
16-02-14, 07:47 PM
Indeed, a 12/12 cycle will induce flowering. A 13/11 cycle will give around 50-60 extra hours of light during flowering, something the plant would enjoy wholeheartedly.

Do you think the plant would produce more in light or dark?
Imho, Having a 11on 13off cycle would save 50-60 hours light energy () and give the plants more of a rest period and resin production increase?

TheKraken
17-02-14, 02:25 AM
Do you think the plant would produce more in light or dark?
Imho, Having a 11on 13off cycle would save 50-60 hours light energy () and give the plants more of a rest period and resin production increase?

I would think that more light would produce more bud. I haven't actually done a photoperiod grow yet but I have heard only good things about the extra light.

Alzy
17-02-14, 11:08 PM
I would think that more light would produce more bud. I haven't actually done a photoperiod grow yet but I have heard only good things about the extra light.

I was thinking along the lines of resin production. Does a bigger bud have more/higher THC content? Obviously harvest time is essential.