I can't say I'm 1) good at math, or 2) have read this entire thread, but you have a 50/50 chance of being right whatever technique you use to guess the sex of a plant before it shows preflowers (also if you cull what you take to be males prior to preflower you never find out whether you were correct). Unless you're working on a pretty large scale this doesn't seem scientific at all.
Everybody farts.
I intentionally grew out 2 out of 4 males for seeds on the last grow.
The main thing that I noticed - it takes A LOT longer for a real male to drop pollen than I thought it would.
Preflower - the male bract(?) were round & smaller than the spade shaped female - and I was wrong on two females....
Flower - is when sex became obvious. Instead of a single bract, the males have bunches that resemble micro-watermelons (on Herijuana anyway...).
--- From the time I ID'd the males (and returned the females to the flower tent) to the time they began to drop pollen was over a week - PLENTY of time to cull two of the males (not as full or vigorous...).
--- Both males put on a frost show in flower and made great dry ice hash!
