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how to produce mostly females from standard seeds.

Discussion in 'Indoor Marijuana Growing' started by charlesCarnage, Jan 29, 2011.

  1. found some great information, if this has already been posted let me know, I will delete it.


    Here Is How To Produce Mostly Females From Standard Seeds

    as written by "Strawdog",
    copied and submitted by mutt.

    As a marijuana grower I always believed that weed seed was genetically predisposed to its sexual orientation as soon as fertilization of the ovule took place in the female. Basically this means that if you take a single female marijuana plant and produced cannabis seeds from her that the ratios are already set in the offspring. If a gender detection test could be established the males could be separated from the females there are then. If this were true then the breeder's packs of ten seeds per pack could easily turn out to be all males or all females because of this genetic predisposition. However this is not the case!
    \t\t\t\tOne of the areas of my interest was in the feminized marijuana seed programs that so successfully charged through-the-roof prices on weed seeds that are reported to grow all females. However, as many marijuana growers like myself have experienced - this is not always the case either!

    Feminized cannabis seeds work on the bases that there is a genetic predisposition for the plant to produce females because of special treatment that it gets in the selfing stages of a unique XX female. I won't go into this in detail here because there is enough information on the process across the entire internet. Anyhow, in an optimal growing environment it is very easy to produce ALL females from these treated female marijuana plants. OPTIMAL is the key word here because in less than optimal marijuana growing conditions strange things start to happen to these feminized weed seeds.
    In a single pack of feminized seeds a grower can produce:



    Yeah, that's right. Males! So where are these males coming from and how are they making there way into the feminized cannabis seed process. The answer is a very simple one. Sex is not completely determined in the cannabis plant until a few weeks before flowering. We will talk about this in a moment but now back to the feminized weed seeds.
    In optimal cannabis growing conditions feminized marijuana seeds will kick out 100% females. This says a lot for marijuana growing conditions and the actual role they play on cannabis gender development. How many times have cannabis growers seen these effects of multiple genders from Feminized weed seeds? The answer lies clearly in how well they grow.

    Weed growers who are growing in non-stressful conditions will never see the male effect from feminized cannabis seeds and so hence it does not exist for them. However over periods time and different weed growing techniques the marijuana grower will eventually see these results when growing in less than optional environments. MALES!
    \t\t\t\tFor this reason marijuana growers who choose feminized cannabis seeds should be forewarned to get their growing environments down to a T. If you prevent stress then you prevent males and hermaphrodites appearing in a feminized marijuana seed population. It is as SIMPLY AS THAT.

    Now onto the real topic of interest. Boosting those female to male ratios.
    As many marijuana growers know cannabis seed banks are not responsible for male to female ratios. If you get a pack of all males, as many of us have done, then a quick call to your marijuana seed bank can maybe help procure some good substitute freebies with your second order. However some will not go along with this. It depends on your relationship with the marijuana seed bank. Give them a call anyhow, that is my advice, but be discreet and don't blame the cannabis seed bank or marijuana breeder.
    \t\t\t\tA couple of years ago Dutch Passion released an essay on how to increase mostly females from a pack of weed seeds. This is an excellent piece of work and has helped me to gain more of an interest in this area. In the past few years I have come to develop my own systems to get those ratios on the up and up. Right now I am very happy to report a real increase in my females from standard weed seeds. Sometimes as high as 90% to 95% on a consistent basis. So how is it done?

    I prefer standard cannabis seeds for numerous reasons. The first reason being that feminized weed seeds come from hermie plants. Whichever way you look at it, the specially treated plants are hermed and this trait is often expressed in the offspring where conditions are less than optimal. Even with standard weed seeds the hermaphrodite condition is still achievable where stress occurs.

    I seem to have noticed that the two most stressful conditions which can cause the hermaphrodite trait occur before marijuana flowering in the vegetative phase of growing is around the 3rd to 4th week of growth before pre-flowering. When the cannabis plant undergoes either heat stress or a problem with the 24/0 or 18/6 photoperiod (whatever vegetative photoperiod choose doesn't matter, as long as disruptions occur). Even during the initial stages of calyx development males and females are obvious side by side at the node region. This is hermaphroditism due to vegetative growth problems.

    In the marijuana flowering period, hermaphrodites generally occur quicker because of an irregular photoperiod than anything else and heat stress certainly helps bananas to pop up in with the marijuana bud. Now, even Sinsemilla cannabis crops will herm towards the end depending on the weed strain. I don't class this as a typical case of hermaphrodites. It is just something that some weed strains naturally do towards the end of the Sinsemilla procedure.

    Anyhow for starters we better reproduce what Dutch Passion have to say about their feminized weed seeds first.

    "Feminised Cannabis Seeds"
    Courtesy of Dutch Passion
    \t\t\t\tIn November 1998 we introduced our "Female Cannabis Seed". We did this after our own experiments showed that from female cannabis seed, we acquired almost 100% female off-spring.

    In the meantime we are six months further on. We have received a lot of feed-back from our customers. The reactions are mostly positive! Clients have successfully produced almost 100% female off-spring. However there have been reactions from customers who found a few hermaphrodites or males plants.

    Apparently environmental influences affect the sex of the female cannabis seeds as well. Because of the fact that Female marijuana seeds do not grow into female marijuana plants under all circumstances. Thus we changed the name from "Female Cannabis Seeds" into "Feminised Cannabis Seeds".

    From literature and from our own findings it appears that the growth of a male or a female cannabis plant from marijunaa seed, except for the predisposition in the gender chromosomes, also depends on various environmental factors. Not only the origination of entirely male or female marijuana plants is partly affected by these environmental factors, the number of male and female cannabis flowers on a hermaphrodite plant is affected as well.

    The environmental factors that influence the sex of the cannabis plant (or the flower in the case of hermaphrodites), are among other things:
    The quantity of nitrogen and potassium of the seedbed. Humidity and moistness of the seedbed.

    Level of temperatures.
    Colour of the light used.
    Length of daylight.

    Stress, any form of stress, makes that more male individuals will originate from seed. Even the taking of cuttings from female cannabis plants may produce male or hermaphrodite cuttings.

    To optimise the result, changes in one or more of the above-mentioned environmental factors for a certain period during marijuana growth, may be applied. During this time these environmental factors will deviate from the standard growing system for maximum harvest and quality, as described in nursery literature. The desired change(s) in the environmental factor(s) are started from the moment that the marijuana seedling has three pairs of real leaves (not counting the seed-lobes). This is the moment that male and/or female predisposition in florescence is being formed. After approximately two weeks the standard growing system can be reconverted to.

    Of the 5 above-mentioned environmental factors the first three are the most practical:

    1. Level of nitrogen and potassium of the seedbed: A heightening of the standard level of nitrogen makes for more female cannabis plants originating from the weed seeds. A lowering of the nitrogen level shows more male cannabis plants. A heightening of the level of potassium tends to show more male marijuana plants, while a lowering of the potassium level shows more female marijuana plants. A combination of a higher nitrogen level for the period of a week or two and a lowering of the potassium level is recommended.
    2. Humidity and moistness of the seedbed: a higher humidity makes for an increase in the number of female cannabis plants from weed seed, a lowering for an increase in male cannabis plants. The same is valid for the moistness of the seedbed.
    3. Level of temperatures: lower temperatures make for a larger number of female marijuana plants, higher temperatures for more male marijuana plants.
    4. Colour of light: more blue light makes for female cannabis plants from seed, more red light makes for more male cannabis plants.
    5. Hours of daylight: few hours of daylight (e.g. 14 hours) makes for more female individuals, a long day (e.g. 18 hours) makes for more male cannabis plants.
    \t\t\t\tNow let me just make a few adjustments here to this. You can do whatever you want to your cannabis plants in seedling stage and early vegetative stage of growth and it will not effect your final male to female ratios. The time when things should be near perfect is in or around the 3rd to 4th week of vegetative growth.

    This is the CRITICAL TIME for getting those female ratios up and up. I realized this clearly when noticing how some cannabis plants hermed because of problems that occurred around this period of the cannabis plants development. If the problems occurred before this time - no herms. So for this reason I surmised that this is when the crucial gender selection is made by the marijuana plant.

    Now I believe that the genders are set in the weed seed however the environment has a massive impact on how this is expressed in the final phenotypic expression of the cannabis plants gender. There are probably many genes that govern this, however lets get into how to up these female ratios.

    The Italian Society of Agricultural Genetics agrees the sexual differentiation of cannabis is strongly influenced by environmental factors such as temperature and photoperiod. Anomalies also occur in floral development like the presence of reproductive structures of the opposite sex, or the development of bisexual inflorescences (monoecious phenotype).

    At the 3rd to 4th week of vegetative growth make sure that your marijuana plants are free from stress. No pests attacks, no fungi attacks, no mold, no irregular photoperiod, not underwatered, not overwatered, not pruned or topped, a cannabis friendly soil mix, not recently transplanted, no small pots. If have these basic growing conditions under control then we can move onto the real forces of female production from standard weed seeds.
    \t\t\t\tN:p:K and nutrients. What this simply boils down to is that you have the right nutrients present in the right ratios. A nutrient formulation that has roughly equal parts N, P and K is great but if the P levels go up or the N levels go down you are starting to look at a flowering type food for cannabis. If you do this then your odds of producing mostly females is greatly decreased. Make sure that you get those N, P and K levels to almost run from higher to lower amounts from N to P and K.

    I have noticed that equal portions of N to P an K can help with the female ratios but the higher N is certainly more helpful. So around the 3rd of 4th week of growth make sure that the ratios are good and that P or K has not gone above the N and P or else more males will occur. Obviously this means to avoid overfeeding your cannabis plants around this time too.

    Never let your medium dry out completely around the 3rd to 4th week of vegetative marijuana growth. If you make sure to water occasionally, but not to overwater your cannabis plants, you will get those female ratios on the up and up. Overwatering or drying out of the medium will only produce more males. For consistent results in getting more females keeps those mediums moist.

    Humidity. Now this is the tricky one. High humidity levels only promote fungi and mold development and lowering humidity levels is the way to cure most of this rot but by keeping those humidity levels up in or around the 70 rH factor will help to produce more females. If you have a low humidity grow room then you should get to hold of a humidifier. Now high humidity levels like 70rH cause the medium to dry out a lot quicker so you got to keep this under control too. Keep those mediums moist and those rH levesl at 70. This will help to improve those female to male ratios. Again, getting them on the up and up.

    If you run the 24/0 photoperiod then do not allow those temps to go anywhere above 85F unless you have an equatorial strain. 75F is the best but going a little lower is not a problem for helping those female ratios. If you can get in at around 65F then those females are going to be popping up all over the place. The problem with this is that some growers like to use the 18/6 photoperiod and when the lights are off the temps drop from around 65F to 50F and even less. Try not to be below 55F because this has the adverse effect on the plants producing more males than females. Again between 65F and 75F is where you want to be during the 3rd to 4th week of vegetative growth, the preference being 70F.

    Invest in a MH Light for vegetative growth. Dump the HPS bulb for flowering later. I have noticed that HPS lighting during vegetative growth simply sends those males to female ratios all over the place. With MH lamps the females are everywhere. Invest in some MH HID lights. It makes all the difference in getting those females to show more often. This is worth repeating! MH Bulbs produce more females under optimal conditions especially if they are present during the 3rd and 4th week of vegetative growth. Surprising enough you can start seedlings under HPS and it will not have an effect on those female ratios. Again the 3rd to 4th week of vegetative growth is what is important here.

    No stress during the 3rd to 4th week of vegetative growth. That is all there is to it. If you got your garden growing in optimal conditions without marijuana plant stress then the impressive 90% to 95% females start to emerge from standard cannabis seed packs. I find that topping is best done at the second to third week of vegetative growth but that this is a little stressful and can lead to those female ratios dropping again. Avoid topping or pruning if you are looking to up the female count.

    That is all I have to say for the moment. These little snippets of information in conjunction with what DP uncovered have helped my female ratios considerably. Hopefully you can see the same results too.
  2. can anyone actually confirm that the grow conditions of the 3rd to 4th week of veg solely determines the sex?
  3. it actually sounds reasonable..... with children all babys are born female... it takes something magical to have a male..... this usually happens at a specific time....

    so in the wild... maybe all plants are female... with stress maybe a plant will turn male to reproduce more seeds to keep the cycle going...

    worth some more investigations... love to see anybody with hard data..

  4. Surely you don't mean in HUMANS?!?!?!
  5. It seems to be pretty good info, I guess it can't hurt to try it.

  6. um what???
  7. #7 toastybiz, Jan 29, 2011
    Last edited by a moderator: Jan 29, 2011
    All it takes is a Y chromosome.

    And I can assure you I was born all male, my parents have shown me the embarrassing photos to prove it...

    And I still don't see anything in the above post that "proves" you can influence gender. Some vague assumptions built onto other vague assumptions. The way in which feminized seeds are produced actually proves that with MJ you need a Y chromosome to make a male.

  8. ahhhh the great debate over mj androgyny....

    speed...i think you may be thinking of the actual reproductive cells. when a baby is "formed" (for lack of a better term) its sex is most def already determined. the chromosomes they inherit from the parents determines this. the females egg can only donate an X since they are XX....and the male can donate either x or y since he is XY. this may be where you think babies are all female at one point which is not true....once an embrio is formed by the reproductive cells the sex is predetermined by the chromosomes inherited.

    though i would def like some concrete information on the topic. seems interesting enough.

    gonna be kinda hard for the folks who dont veg for that long to influence the ratios in this manner.

    what about auto strains? this def cant hold true for strains containing auto traits

    also....this really is stupid in the sense of a 'strategy' for boosting female/male ratios. typically when i grow pot....i try to give it optimum conditions from day 1 all the way untill chop....not just a finite span of the grow.

    and if sex is not determined until so late into its life....then why do i notice sometimes males seem to be leggy right from seed...more so then females?
  9. Not true man, i just looked it up, a humans sex is determined right from the beginning. However, there aren't any physical differences between males and females in early embryonic life (which is apparently why men have nipples... trippy), we do all start with blue eyes though. So if these human traits happen to be transitive towards plants then that would suggest a plants sex is also determined when the seed is created. Realistically though there is no indication of transitivity between them, so im mainly talking out my ass...
  10. 1st off, I am not sure your info is accurate. And 2nd, even if what you said about children is true, that has absolutely nothing to do with plants. Humans and Plants do not relate as far as similarities. Not sure why you would compare something about humans, and try to relate it to a plant.
  11. still, it can't hurt to give it a try.
  12. well.....just by chance I am starting week 3 of vegetation today with my 5 Northern Light babies. My grow tent just also happens to be the "ideal" with the exception of CFL's instead of the mentioned MH lights. I am using all blue spectrum though and I have plenty of lumens for my space. So I'll follow these P,N,K, recommendations and let you guys know my ratio's. But I'm a little afraid of 70% humidity. Seems like I would be begging for fungus. My tent is at 50% and I feel like that is plenty wet. What do you guys think?

  13. You can determine the sex way before then.
  14. I have assisted someone with growing (soil based) for over 25 years. They do not grow on a large scale but enough for personal medical consumption. I have read much about cultivating the crop but have never heard about ways to force plants to become females. I have witnessed females becoming hermies, however.

    For lighting, MH is utilized for the first 3 to 4 weeks at 18/6, switching to HPS 12/12 for the remainder of the grow. Typically three seeds are started and I do not recall ever getting three males, most always at least two are females.

    I find this hypothesis regarding not stressing during the 3-4 week period interesting, as this routine is basically being followed and the resulting experience has been higher percentatages of female than statistics would predict.

    I am quite curious as to whether other growers, who utilize standard practices, such as quality nutrients, appropriate pH, and sufficient lighting, have actually experienced an abnormaly high number of males emerging? Higher than 50/50. Perhaps the plant produces a higher proportion of female pollen, which would account for higher proportions of females.

    If this theory were true, it would seem that one could take clones from a male plant, grow them out under the "proper" conditions and have them flower as females. I suspect very little has been done cloning males as most growers just yank them out.

    Very interesting postulation, worthy of actual research to determine the validity.
  15. i find this all very interesting
  16. I prefer standard cannabis seeds for numerous reasons. The first reason being that feminized weed seeds come from hermie plants. Whichever way you look at it, the specially treated plants are hermed and this trait is often expressed in the offspring where conditions are less than optimal. Even with standard weed seeds the hermaphrodite condition is still achievable where stress occurs.

    I've got a plant right now that was stressed into hermie around the 4th week of flower because of an unnoticable light leek,witch has been taken care of.The plant has a few bananas on it and has already developed a few seeds starting to mature,not to many but there will be a few.So they will be feminized seeds if i decide to grow them in the near future?I hope so!
  17. Feminized seeds are a scam.

    What I don't get is why they are often more than 2 times more expensive.

    I saw Blueberry (non fem) for $50 for 10 seeds.
    The femmed blueberry was $136 for 10 seeds.

    If you bought 2 packs of the non femmed and didn't use the techniques to get mostly females, you would probably get 10 females.

    with one 10 pack of femmed seeds you could get 8-10 females

    So you pay twice as much for basically the same results with possibly worse genetics?

    I don't get the appeal.
  18. With alligators temputure can effect male female ratios
  19. This all sounds good and all but isn't it important to maintain optimal grow conditions at all times during the grow anyway. I mean. Not to be a jerk but noone is gonna use CFL lighting throughout their enitre grow except during the third and four weeks at which point they switch it up to a thousand watt MH. I'm sure it is important during this time period and I see what you're saying but... everyone is trying to get the best out of their enviornments at all times... not just certain stages of development.
  20. [FONT=&quot]
    No they don't.

    They are not a scam. I've been growing femmed for years and have never had a hermie or male from them. They cost more because they're worth it -- 10 regular seeds could yield 5 females, or 7, or 3, or some other number. No one knows until you grow them out. Then you toss the males (half on average) so you only really ended up with 5 of your 10 original seeds. So paying double for femmed seeds means on a per-female-seed basis the cost is the same. But it doesn't end there. First off, I find femmed seeds for less than double. But more importantly, to get to the point where you cull the males you have to grow out all your seeds, which means more pots, more soil, more lights, bigger space, more ventilation, more nutes consumed, bigger electric bill, etc. Feminized seeds, in contrast, are very economical.


    I agree you want to optimize all aspects of your grow all the time no matter what. Your yield is the end result of a chain of circumstances and events, and like any chain it is only as strong as its weakest link. But, you're not accurate about what others do, many grow with only CFL and/or do not otherwise try to maximize grow conditions, thus the constant flood of posts here on GC from folks wondering how they can get their plant to tolerate high heat or extreme cold (rather than figuring out how to control grow temps), asking if they not only can use just CFLs through the entire grow but if they can use way less than the bare minimum recommended wattage when using CFLs, use cheap chemical ferts, have plant health issues but don't know the pH because they haven't bought a gauge, wonder if it's bad for the plants if the light cycle varies from turning it on and off by hand every day rather than getting a timer, etc etc etc.

    I wish more growers were as buttoned up as you and me about it.

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