In his book, Indoor Marijuana Horticulture, The Indoor Bible, Jorge Cervantes claims that these conditions produce more females: High humidity, low temps, more blue light, fewer hours of daylight. The opposite conditions and any stresses produce more males. I'm of the opinion that he may be right, but the percentage increase in the odds from adjusting all that stuff is small enough that for us just planting one more seed increases our chances for females more.hey everyone i have a quick question......is there anything that can be done to seeds or young plants to encourage females......i once heard that blowing on your seeds would help because of the carbon dioxide, but im not sure.....any help at all would be killer.....thanks