Factors affecting male/female ratios in cannabis populations

Post or find info about breeding cannabis, creating hybrids, genetics etc

Here are my thoughts about what can influence the sex of cannabis plants.

Theoretical when you buy a pack of seeds from a quality seed bank you should, on average, end up with 50% female plants and 50% male plants when you grow your seeds. Sometimes this ratio may vary and you may end up with more females then males which is more often than not the norm, or the plants may all be of the same sex. What are the naturally occouring factors that influence this ratio?

If the seeds were not deliberately bred by the breeder to be all female (by crossing hermaphrodite female plants with pure female plants) then the only sex determining factors that remain are environmental. These remaining factors can be listed as follows:

1 .Nutrient concentrations and PH of the soil or grow media

2. Length of the nights or light cycles and quality of light

3 .Location of the population and the density of plants in that location.


All of the above can affect the ratio of male/female plants in a cannabis population. The purpose or reason if you like, of a cannabis plant's existence is the same as all other life on this planet, (including humans), reproduction! They exist and grow only to reproduce and pass genetic material on to the next generation of offspring thereby perpetuating the existence of the species.

Cannabis plants that are growing wild in an area where soil quality is poor, water is scarce and or there are so many plants that overcrowding and root binding is a problem, should theoretically tend towards a higher male ratio among the population. The logic behind this theory is that a higher ratio of male plants will give the population greater mobility. The wind may carry the pollen from the taller male plants to a female plant in another location, sometimes many kilometres from the original location of the male plant, thereby allowing the next generation of the population a chance at finding a more suitable location to grow and joining a new gene pool. Similarly, the same could be said of a population that is growing in a shady area where the amount of direct sun light they receive each day is limited. Plants that receive little direct sun light will stretch in an effort to reach the light source. This may also cause sex reversal in cannabis plants and result in taller plants that have a greater chance to spread their pollen and thus, the genes of the population. A population that is growing in an area where the soil is very fertile, rain fall is good and the environmental conditions are luxurious (from the plants perspective) should tend towards a higher ratio of female plants.

This theory does not mean that it's impossible to grow a female cannabis plant in poor quality soil in a shady location, just that the chances of a plant grown from seed being female will be increased if the growing conditions are favourable. Of couse, I could be wrong 8)

I don't think the environment makes a plant produce more or less males or females, the environment determines of those seeds which survive.

Doesn't genetics come into it somewhere? :wink:
Peace...

genetics do come into it, but the plants sex isn't determined until th eseed has germinated. Thats why if you soak your seeds in hormone (giberellin, i believe) it's possible to get a much higher ratio of females:males, or so i've been told at least. I think that if genetics was the only determining factor in sex of th eplant, then you'd probably see far less hermies....or not!?! anyone else got $0.02 to add?

only a rumour mill....if you germinate the seeds in soil 5 inches or deeper you will have a higher percentage of females.........

@luke, genetics are the most important factor but other factors can have an effect after the plant has begun growing. You could start of with a female plant and then expose it to environmental stress and end up with a female which also has male flowers. There are also chemicals you can use that are reputed to be able to change the sex of cannabis plants but I have never tried them and can't really say for sure if they have any affect.

My original post is not based of fact, just my observations.

yeah. that's strange. last grow. I only had 3 out of 10 were hermie.
this grow I've got 10 hermie and 2 female. never had a male in my grow yet.

I'm just wondering. does the plant's sex determined after it's geminated? or before flower period?

From what I can tell the sex of a plant can be affected at any time during the growth cycle. If you have good seeds (no hermies) then the chances of stress affecting the sex of the plant are reduced.

whatever herbalicous said, better mean that "if you grow seeds from PS, there is chance of you getting hermie!"

Even the best seeds in the world could be made to go hermie if you stressed them, but with good quality seeds the chances are reduced. So if you do a good job of growing then your seeds from PS should be 100% of one sex ie: the males will be males and the females, females, none of this hermie shit.

@seeker...are you growing from bag-seed, or where did you get the plants from? did you do anything that you can think of, to stress the plants? Are you growing in hydro or soil? (doesn't make too much difference, but soil seems to be more forgiving)

If I were you... (easy to say this when not looking at your plants)...id consider pulling all of them, depending on how hermie your 10 plants are and just starting over...I've had friends who ended up with more than 2/3 of the flower weight being seed...ie out of 30 grams of flowers, over 20 grams was seed. If you got heaps of hermies, order some seed now and just keep growing the others until the mew seedlings are ready to take their place.

Lots of luck, whatever you do.
Marduk 8)

Seeker wrote:whatever herbalicous said, better mean that "if you grow seeds from PS, there is chance of you getting hermie!"


Hi Seeker. Did you buy some seeds from Planetskunk and some of them turned out hermaphrodite? If you did then we would like to know about it; what strain it was, seed company, so we can contact them and ask for an explanation. We don't sell feminized seeds so you should not find any hermaphrodite plants in any seeds you buy from Planetskunk. If you did buy seeds from us (I think I remember you ordering some), then you will know that all the seeds sold on Planetskunk come in their original unopened packaging.

If for some reason you are not satisfied with the seeds you received from us then email orders@planetskunk.com and let us know what the problem is.

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