Indoor 12/12 vs 20/4

[Matteo21]

I have seen more than one discussion on people using 12/12 vs the 20/4. I want to know if anyone has taken the same strain same conditions(as close as possible) and done a full grow with 12/12 and one with 20/4 and did a full "study" on exactly what the outcome was yield wise. Looking for some figures/weights not just it was a little bigger or smaller.

 

[realcarlos]

Hey Matteo
You're talking about two different types of Cannabis photo strains (which need 12/12 to flower) and true auto strains which will flower under any light regime
I guess you're talking about 12/12 from seed for photo strains. I have seen some grows done by using 12/12 from seed. They were very impressive. From a couple of grams to a couple of ounces. But it all depends on strain. Some say 12/12 from seed is unstable

20/4 18/6 is recommend for auto strains anything less than that will diminish yields

You can't really do a 'study' between the two as they're different types of cannabis. Also a photo strain won't flower under 20/4

 

[frankreynolds]

I don't know it he was talking about this but there were some people who were doing 12/12 from seed with autos trying to get quicker yields (some actually succeeded). If I recall correctly it was in the breeding section of another forum

 

[realcarlos]

Welcome to the site Frank
but I think those people switched to 12/12 because they weren't true autoflowers
or didn't have the patience and wanted a quicker but diminished yield

 

[Mr Piggy]

The way I understand most autos(referring to rudi based ones) 12/12 or 20/4 won't make a difference in triggering flower. It's done by a recessive gene that works on it's own schedule. 12/12 would just give diminished results.

Could the op clear up their intention and/or link to the grow they're referring to?

 

[Matteo21]

I want to clarify what I am asking in this thread. I am talking about true auto plants not photo period plants. I understand that they will flower either way. I want to know if anyone has taken the same strain(autoflowering strain not photo) same conditions(as close as possible) and done a full grow with 12/12 and one with 20/4 and did a full "study" on exactly what the outcome was yield wise. Looking for some figures/weights not just it was a little bigger or smaller. Just from a point of electrical usage 12 hours would be cheaper but does it effect yield enough to make it a bad choice?

 

[Mr Piggy]

Yes, your yields will be diminished. One of the reason people can get such huge autos inside is the fact they can bud under many hours of light. More hours a day spent producing bud under light = more bud. I don't know about "full study" but I've seen many a grow online over the years where people throw autos in their 12/12 flowering room and are disappointed with the results. This is all hearsay of course as for the life of me I can't link you to one right now. But reducing your lighting schedule will for sure hurt your return, that's why everyone runs 20/4.

 

[gtron]

For personal grows I can't imagine the electrical cost for running 250w for instance being significantly different running 20/4 over 12/12. Obviously energy cost would determine that, but I live in an area of the country with fairly high electric costs and I did not notice a big increase with my 240w blackstar, 4bulb t5, circulation fan, exhaust fan running 24hr. Then when i reduced the light to 12/12 for a photo, still no big change. It could have been as much as $10 a month difference, but I doubt it.
Now if you are talking about a big grow room with some serious HPS and the supporting fans and ac, yeah that would make a difference. But if someone were seriously thinking along those lines, they need to do real number crunching on their own. Because just asking for advice from a forum is not going to break things down by dollars & cents. Then your talking a business and you should have a business plan laying out all your costs & expenses anyway. And every area has their own nuances that could have a big effect on the bottom line.

 

[Mr Piggy]

I noticed a big decrease this round as I went back to 12/12 for a photo grow. Of course, ten to twenty is a huge sum to me. I'm dirt poor. I'm still going to run my autos 20/4. Might as well get as much as I can out of them.

 

[spelsylver]

i was forced to run my syrup under 12/12 lighting to make room for my photos a couple grows back...i was really looking forward to the syrup because of other people's results yeilding more than an ounce per plant. Under 12/12 my syrup suffered greatly, even in a dwc bucket and in the end was not worth it. Wound up with about 7 grams. good quality but still, not worth it and i went 70 something days.

with autos i've found root space + plenty of light = biggest buds. No side by side test necessary to determine this.