Doobsday, nothing mean intended, but every time I turn around you are giving answers with nothing to back it up with, purely your opinions. When people come asking for advice, they are anxious to get the info they want, but they want facts. Remember when you were just learning, and how much mis-information you found? It got to the point that you had to take notes when you found a reliable source, because there is so much crap out there to be had. Becoming a source of quality information only helps to further this glorious plant all that much more.
Green Nobody gave some good advice as usual. GreenNobody IS somebody.
(lol, now you know I'm stoned)
420in808, everybody is going to have an opinion on every question that you can think to ask, you need to decide what info to keep and what to discard, on your own. So simply put, you need to have some good ol common sense.
I wondered this very same question, and got all kinds of weird and stupid answers as I researched it. (I was told about, and even tried the birth control method.) The best info I could come up with came from 2 different sources, (1) an old timer, organic grower who I trust totally. When this person gives me advice, I shut up and listen....and I take notes. This person taught me about the molasses trick I shared with this forum earlier.
(2) I figured....go to the source, go to the seed experts, so I went to Dutch Passion seed company to get answers. This is what I learned form DP:
From literature and our own findings it appears that the growth of a male or female plant from seed, except for the predisposition in the gender chromosomes, also depends on various environmental factors.
The environmental factors that influence gender are:
* a higher nitrogen concentration will give more females.
* a higher potassium concentration will give more males.
* a higher humidity will give more females.
* a lower temperature will give more females.
* more blue light will give more females.
* Fewer hours of light will give more females.
It is important to start these changes at the three-pairs-of-leaves stage and continue for two or three weeks, before reverting to standard conditions.
My organic grower friend tells me that she uses this method all the time, and she is way too cheap to ever buy feminized seeds, she tells me that she averages a 90% female to male ratio.
There's a thread somewhere here on this very subject.
I hope you find this as helpful as I did when I got it.
Peace