switching to lights on at night...

Humanrob

Humanrob

Well-Known Member
This is my first grow, and I don't know if this is a stupid question, so be kind…

I've been running my veg 18/6 from 6am to midnight. I realized that my flowering is going to extend into late spring when daytime temps will rise, and I'll need to switch my "lights on" time to night time hours to keep the room cool -- I'll be doing my 12/12 with the lights on from 10pm to 10am.

In order to make this switch when I flip to flower, I can't help but disrupt the cycle. As best I can figure, I'll either have to leave the lights on for 26 continuous hours (going on at current on time 6am, and not shutting off until the next morning at new off time, 10am), or have them off for 22 straight hours (shutting off at current midnight, and not turning back on again until the next night at new new on time, 10pm).

Which is less disruptive/shocking for the plant? If it doesn't really matter, that's good to know too.
 
A

az2000

Well-Known Member
You could move the start time one hour backwards for 8 days. (6am, 5am, etc.). Leave it 18/6. It would effectively get an extra hour a day because the off time would be reduced an hour. Maybe reduce the on time 30 minutes each day, easing into 12/12. It would start at 18.5, and go down to 15 hours "on" at the end of 8 days. At that point, cut it 3 hours to 12/12.

If you worked it out on paper you could get there more precisely over 8 days, landing on 12/12 the last day.

I don't think it's a problem to give them more light, which is what would happen if you move backwards every day without changing the 18/6 period. It's just that, if you're going to go to 12/12 anyway, you could get there incrementally while moving it back. Wouldn't have to be 8 days either. Could do it in 4.

You just don't want it bouncing around between less, more, less. You can work it out on paper so that doesn't happen (if you want to reduce the light period while moving it backwards, which increases the light period).
 
Humanrob

Humanrob

Well-Known Member
az2000 said:
You could move the start time one hour backwards for 8 days. (6am, 5am, etc.). Leave it 18/6. It would effectively get an extra hour a day because the off time would be reduced an hour. Maybe reduce the on time 30 minutes each day, easing into 12/12. It would start at 18.5, and go down to 15 hours "on" at the end of 8 days. At that point, cut it 3 hours to 12/12.

If you worked it out on paper you could get there more precisely over 8 days, landing on 12/12 the last day.

I don't think it's a problem to give them more light, which is what would happen if you move backwards every day without changing the 18/6 period. It's just that, if you're going to go to 12/12 anyway, you could get there incrementally while moving it back. Wouldn't have to be 8 days either. Could do it in 4.

You just don't want it bouncing around between less, more, less. You can work it out on paper so that doesn't happen (if you want to reduce the light period while moving it backwards, which increases the light period).
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Thanks for that perspective. That wouldn't be that hard to do, rolling the time change on the timers incrementally over a week or so. I was thinking, that since I have a multiple CFL set up, over the course of a week I was going to start to swap out the 6500k's for 2700k's, so I could overlap those two events.
 
A

az2000

Well-Known Member
Humanrob said:
rolling the time change on the timers incrementally over a week or so.
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Be aware that there's a balance between doing it abruptly in one day (with a 22 hour lights out) and reducing the light over many days. For example, the longer you spread it over, the more days the plants will be between 12 and 18 "on." Receiving less than optimal light, but not so little that they can start flowering.

If you got creative and did it over two weeks, I think there would be too many days where the plants would be in that less-than-ideal 18 area, but not in the productive 12 area either.

On the other hand, it's ambiguous what a "day" is if you move the "on" time back 3 hours a day for 4-5 days, while also reducing the "on" time. You'd be working with days that are ~10% shorter while trying to spread "on" and "off" from 3:1 ratio to 1:1 ratio. And then bounce back to a 10% longer day.

You could visualize it with lines drawn on paper. It won't be hard to do. But, my point is that there's a balance between an abrupt 90% shorter day if you do it in one day, and starving the plant for light (while not being in the productive level of starvation where flowering begins) if you try to spread it over too many days.

3-6 days sounds decent to me.
 
Humanrob

Humanrob

Well-Known Member
az2000 said:
You could visualize it with lines drawn on paper. It won't be hard to do.
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I think I get it, thanks. And as far as visualizing, for me drawing a 24 hour clock (instead of the U.S. 12 hour version) and then drawing in partial circles to account for the on-times, seemed to help me map it out.

It'll be a couple of weeks before I flip them, I just have too much time on my hands so I'm thinking ahead. Thanks again for your input. :)
 
atxlsgun

atxlsgun

Well-Known Member
If you want them to get bigger keep vegging if you want to start flowering flip the lights and the countdown begins if you want to change light schedule in veg just change it, you should veg 24 hours if you can though

Sent from my D6616 using Rollitup mobile app
 
atxlsgun

atxlsgun

Well-Known Member
Fuck giving your ballasts a break they work for you and are easily replaced just have a fan on em it'll keep em cool that's what I do with two lumatek dual 600's and they don't even have an internal fan haven't had a problem yet

Sent from my D6616 using Rollitup mobile app
 
Tim Fox

Tim Fox

Well-Known Member
Humaresearch post: 11403982 said:
Tim, you're not implying that I'm thinking too much… again… :lol:
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They are so resealant lots of light flipping . can cunfuse them but changing your on off time, not so much, chose your doing greatyour new timer setting and wing it,,
 
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