Thatās more of a regional thing, for example closer to the equator with seeds from that region might be able to grow starting in 11/13 light/dark and gradually work towards 13/11 gaining a minute a day
In some cases it could also be different spectrums of light, had 2 plants last year I moved to a different grow area with a different spectrum of light color under 24h of light and it started to flower and went back to reveg just having em under different light units quantum---->blurple
Caution:
Sharp learning curve aheadā¦
Cheers
G
All F1s should have 1 copy of the auto gene. So you can just pick whatever plants you like best. Fastest finishing might make for faster autos, but the %s wont change. F2s you just have to do as you said, and let them veg until the autos show themselves. The F2s are harder, especially if you have males too. 25% will be autos, so 1 in 4, but that means only 1 in 8 will be an auto female. I ran enough to find 4 females and 3 males when I did it. F2 is the harder part imo.
AZsea pretty much answered your question, so Iāll just leave this link here.
This is also my understanding. Semi auto is a misnomerā¦ thereās no auto genes in semi autos.
Donāt start throwing chairs just yet OG. Now with the everything x everything trend, there are semi autos fast versions to further confuse growersā¦
Proper semi autos are just plants or lines selected to flower under longer hours, usually anytime after the summer solstice and they flip real fast, skipping the weeks of transition.
They have their purposeā¦ but can be a pita to keep a mom from. I always plant 25% semi autos, they can save you from a crappy outdoor season.
I think it is a spectrum. auto-fast finishing- slow finishing.
I havenāt read every post but the simplest answer is the one involving mendelian genetics. An auto cross and a photo cross will result in plants that are (1/2auto) photo. The auto half is unexpressed. Now if you take those plant and run an f2 then THIS generation will be 25% auto. You donāt need to cull from the F1 generation to get auto plants in the f2 generation.
.5x.5= .25 or 25% auto.
The reason autos are not expressed even though it is 50% of the genetics in the F1 generation is because the auto trait is recessive, therefore to express itself, it must be on both alleles in the F2. 1/4 of F2 will be 100% auto.
Hope that helps.
Oh, @Hashton_Kusha, I sent an email to the Greenspace ppl about seed NFTs and they responded saying āthey would take my ideaā. Not sure what that means but seems positive 
. (Like specifically geared toward seed batch numbers and lot etc.)