Straight from dutch passion
n an experiment done in 1999 we grew 15 varieties of "feminized" seeds. We started with 30 seeds per variety. The goals were: 1) to determine the percentages of female, male, and hermaphroditic plants. 2) to compare the uniformity (homogeneity) among plants from "feminized" seeds with those grown from "regular" seeds.
1. The results were excellent. Nine out of fifteen varieties had 100% female offspring. Percentages of female plants from the other 6 varieties were between 80 and 90%. These plants were all hermaphrodites, producing their male flowers at the end of their lifecycle. Seed-setting hardly took place. No males were found.
2. Approximately 70% of the plants of varieties grown from "feminized" seeds were far more uniform than plants grown from "regular" seeds of the same variety. About 20% of the varieties were a little more uniform, while in 10% of the varieties no difference in uniformity was seen.
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.
To produce our feminized seeds, we start with selected female clones. Under standard conditions these female clones do not produce any male flowers. By the method we found, we are able to have these female clones produce abundant male flowers and pollen (see photos). The pollen thus produced we use for the production of our "feminized" seeds.
