Genetic and/or environmental pressures leading to herm in autos?

[terp182]

I've run about 8 or 9 auto grows now, and in the first 7 grows, I've run mostly 20/4 and 24/0 lights. Using Megacrop in autopots in soil, no nutes until about day 25. However, in my last two grows now, both 24/0, I've gotten herms. The first was an Ace Seeds Auto Malawi x NL at around 100 days, and in my current grow I just had a Mephisto Strawberry Nuggets, super squat indica megabud pheno, also herm and produce pollen at around day 76. Another SN pheno did not.

The only two factors I'm sure are different these last two grows are the lights being on 24/0 (dialed into about 35-40 DLI), and having gotten a Hurricane fan (the smaller one) which is scheduled to run 30 minutes of every hour (15 on/15 off), but sometimes I leave it on for a few hours at a time. Even on low, that thing blows air like crazy. I also have a small oscillating fan on 50% that runs constantly at the top-of-the-pot level to keep air circulating and discourage fungus gnats.

I searched this and the Q&A forums but I don't know if it's been explicitly discussed. What exactly are the genetic and environmental factors that might increase the probability of getting a herm in autos specifically, if any? Could it be "too much wind" or "too much light" or both that are affecting this, or did I just get some bad luck and roll snake eyes a couple times in a row? I appreciate any insight you guys might have!

 

[Badfinger]

I have done all my grows with an 18/6 light schedule, with two 6" oscillating fans on low, just enough for a gentle breeze. Last grow I got my very first hermie, it was an NL freebie. Which I caught late, and immediately did an early harvest on my grow. In my case, I'm now leery of trying anymore freebies. Except jean-O's freebies, cause he throws you a whole pack of one of his regular product line.
Seed banks tend to throw you seeds they get in bulk for just that reason, and cant even tell you who the breeder could be.

 

[parsing_trees]

I searched this and the Q&A forums but I don't know if it's been explicitly discussed. What exactly are the genetic and environmental factors that might increase the probability of getting a herm in autos specifically, if any? Could it be "too much wind" or "too much light" or both that are affecting this, or did I just get some bad luck and roll snake eyes a couple times in a row? I appreciate any insight you guys might have!

Too much light intensity can definitely do it -- I've had an otherwise healthy plant grow a few stamens when it stretched into a light.

I haven't seen an exhaustive list, but any stress that can cause photoperiods to herm, aside from light leaks in flower. Intersex traits aren't specific to autos, and lots of photoperiod clone-onlys getting crossed into autos are known to herm: Cookies, Sour Diesel, GG#4, etc.

 

[terp182]

Too much light intensity can definitely do it -- I've had an otherwise healthy plant grow a few stamens when it stretched into a light.

I haven't seen an exhaustive list, but any stress that can cause photoperiods to herm, aside from light leaks in flower. Intersex traits aren't specific to autos, and lots of photoperiod clone-onlys getting crossed into autos are known to herm: Cookies, Sour Diesel, GG#4, etc.

I didn’t mean to frame it as an auto only issue… I’m familiar with intersex traits in photos and until a couple cycles ago, thought it wasn’t an issue with autos at all since I hadn’t encountered it.

I think my environment may be too bright - I’m also going to invest in a light meter finally. Photone ain’t cutting it.

Two herms in 8 cycles isn’t bad though, but I wanted to double check if there was something I could adjust to reduce the probability of reoccurrence. I hope this addresses it! I appreciate the replies!