Plant Sex...Can Environmental Factors Play a Role?

Just looking for anyone with real experience with environmental factors influencing male or female sex. Seeing a high ratio of males and just curious if anything I'm doing is influencing it or just bad luck. Thanks.

Apparently higher temps in seedling stage can raise the ratio of males, aswell as excessive temp swings I believe. There are more factors which can influence it aswell, now that said I dont know just how much sex can be influenced. I think it was @Dr. Who who made a informative post on the subject

I posted a thread about this a while back, a website which talked about differences in humidities playing a role too

My temps are pretty steady, 70's, low 80's

Its very possible that you just had bad luck, I dont think that even if you kept all the conditions in the range to influence sex to be male, that very many would be "influenced" enough to "change" If it were this easy to influence plants sexual expression I feel like rooms that arent tuned in would not be able to produce any appreciable quantity of bud. Not saying it cant play a role, but you probably just had some bad luck imo.

dynospec said:

Its very possible that you just had bad luck, I dont think that even if you kept all the conditions in the range to influence sex to be male, that very many would be "influenced" enough to "change" If it were this easy to influence plants sexual expression I feel like rooms that arent tuned in would not be able to produce any appreciable quantity of bud. Not saying it cant play a role, but you probably just had some bad luck imo.

Click to expand...

You're probably right. First run of 4, 3:1. 2nd group, 5:2. Seeing some potential males in this next group of 4, preflowers just forming. I've been working to get mother's and cloning, but high male ratios have been frustrating.

I'm finally reading Jorge Cervantes' book, he actually lists several factors that can play a role. I'll post em in a bit.

"Grow More Females from Seed Environmental factors start influencing sex the moment the seedling has three pairs of true leaves (not counting cotyledons). Environmental factors that influence sex determination of cannabis include but are not limited to:

Increasing the level of nitrogen makes more female plants. Lower the nitrogen level to create more male plants.

Increase the level of potassium to increase male tendencies; lowering the potassium level encourages female plants. A higher nitrogen level and a lower potassium level for the first two weeks increases females.

Low temperatures increase the number of female plants. Warm temperatures make more male plants. High humidity increases the number of female plants. Low humidity increases male plants.

Low growing-medium moisture increases males.

More blue light increases the number of female plants. More red light increases male tendencies. Fewer hours of daylight (e.g. 14 hours) increases the number of females. Longer days (e.g. 18 hours) make more male plants.

Stress: any environmental stress tends to yield more male plants when growing from seed."

- Marijuana Horticulture, Jorge Cervantes