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Connection between 24hr lights & males

Discussion in 'General Marijuana Growing' started by videoman40, Mar 15, 2007.


    videoman40 Well-Known Member

    I just made a post, and it got me to thinking after I posted it. I was posting in a thread where he was bitching about getting all males, and rightfully so. I'd be pissed if that happened to me too.
    My post included a quote from dutch passion seed company that says:

    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.

    What got me to thinking was the line that said: Fewer hours of light will give more females. The reason I point this out is, I've seen a few debates recently about 18/6 lighting vs 24/0 lighting.

    If the above paragraph is correct and true, wouldn't 24/0 produce more males?

    AssGasOrGrass Active Member

    I hope not, i always here people going with 18/6 to save on the bill and that 24 is better, when i grow im gonna use 18/6 for money saving. So all in all. if 24 does give more males than 18/6 is the best way to go.

    pauliojr Well-Known Member

    Using 16/8 on the past grow about 80% turned out to be female. That is even less lighting then the 18/6. Maybe a connection there?

    Someone should do a grow test where 10 random seeds are in 16/8, 18/6, and 24/0 using everything else exactly the same besides the lighting hours to see which ones produce more females and males (same lighting, ventilation, bulbs, etc.) Anyone up to the task? I would, but no room and broke as shit lol.

    muu232 Well-Known Member

    Well from that quote, I'd say yes, that 24/0 would produce more males. 24/0 is definately not the way to go. The dark cycle is very important for plant growth as it causes stronger root development which means stronger, bigger, healthier plants. I always go with 18/6. So with 18/6 you would have a better root system, and better chance of females. Is there any reason at all to go 24/0??

    FilthyFletch Mr I Can Do That For Half

    I alsways used 24 hour floros for new seedlings and have about 80% female production as long as I use good seed.Now with bag seed its a crap shoot anyway you slice it.My babies stay 24 hours for at least 2 weeks then 2 weeks 18/6 (maybe more if I want bigger plants) then 12/12 for flower.

    blackout Well-Known Member

    i am using 24/0 on my new clones as my timer blew it,s arse,it has only been a few days,but have never done it before,so of to get a new timer this weekend when i head into the big smell to get my supplies for the month,so hope no hermies,but i always figure every living thing needs to sleep,but lots say they do use 24/0 not my scene though?

    mr_issues Well-Known Member

    So if I use the 16/8 light setting untill they flower, then drop them down to 12/12 I should get some pretty damn good buds right? Im still a little new to the way im doing this. Never used seeds before untill now.

    videoman40 Well-Known Member

    AssGasOrGrass, I never heard that 24/0 was better. I have heard arguments on both sides of the fence, however I have always felt it is best to try to mimmick mother nature. So it's 18/6 for me.

    PaulioJr, your results are exactly what they are saying to do: "Fewer hours of light will give more females." Using 16/8 was smart.

    I have a friend who uses these guidelines on all grows, and claims a 90% ratio of females.


    AssGasOrGrass Active Member

    Yeah exactly i think the whole point of indoor growing is to try to mimmick mother nature.

    Godkas Well-Known Member

    I dont know this for sure yet but i've had similar thoughts. I had my lights on 24/7 for the sprouts into the first week of growth but aborted the idea in favor of strong healthy root growth.

    I think its feasable.

    videoman40 Well-Known Member

    No Dude, Re-read this part: 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

    Garden Knowm

    Garden Knowm The Love Doctor

    There are a few solid studies that show plants do better with daily darkness as opposed to 24/0

    It is always a good idea to give the equipment(lights, fans, pumps, etc.) and plants a rest.


    FilthyFletch Mr I Can Do That For Half

    As always seems to be a matter of personal preference.I also say that mimicing mother nature inside defeats the purpose as with indoor conditions you want to exceed mother natures options to get the speed and quality mother nature doesnt allow for.Hell if I was growing indoors and had to wait 6 months to harvest Id be pissed lolTrial and error brings preference and content.

    Godkas Well-Known Member

    I dunno fletch you gotta remember plants are adapted to the sun and its cycles.

    FilthyFletch Mr I Can Do That For Half

    But would you also not see the side, as I am a clone grower from clone growere that go back years from original seed, that through forced adaptation of indoor growth a plant can be adapted to an inside controlled environment in the same way natures selective adaptation has occurred. A sort of if you will evolution to what generations of growers have trained a starin to be which is genetically passed from cloned mom to clone baby then to next generations also??

    lando421 Well-Known Member

    VIDEO man you are covering something i am very interested in!

    I was told by the guy I bought my seeds from (local head shop) that 24h lighting will give approximatly 70% males, while 18/6 brings it to around 50/50 and 16hours 40% chance of males...Those are obviously rough stats and very dependant on the strain and other conditions.
    I found it particularly strange because I haven't read that anywhere, or seen any sort of tricks to help the male to female ratio.
    I posted something about it on a 24h vs 18h lighting debate and people just politely called me a moron. Thats ok though, I can roll with the punches...

    Glad to see some info from a credited fella backing up my thoughts...


    Godkas Well-Known Member

    This is what I am afraid of. We may be destroying the genetics of marijuana. Over time the strain might change, better or worse.

    FilthyFletch Mr I Can Do That For Half

    Maybe so but for indoor grows a time scheduele that allows fro optimol production and yeild ina know faster pace does have its advantages.I always am impressed by those out door growers who can put so much time and effort into such long grows but have always figured if Im not growing an acre or more of bud I can get the same yeild indoors with 3 harvests in the same time period with 3 stages of succesfull satifaction without 60% of the effort or stress.Im a believer in the 24 hours on cycle for starting then a slow darking period following a more natural light cycle or season change but find the 24 hours gets me a jump start into real vegging.I do respect others preferences though so Im always saying if it works for you go for it if not maybe try what the other guy does.Good grows either way

    videoman40 Well-Known Member

    I do have a friend who uses all these guidelines on all grows, and claims a 90% ratio of females. That is impressive.

    Filthy, I think you would be hard pressed to outdo mother nature, as I re-read your post, I kept wondering if you were growing for personal or for profit, it sounds like it's for profit. How can you out do mother nature, a well grown plant outdoors can yeild over a pound, a well grown plant inside can yeild....ounces.

    I could think, and wonder if 24 hour light would speed up vegging, however from all the reading I've done, I have never found any info to support this theory. Only an increased electric bill. I also agree with GardenKnowm that giving the equipment a rest is important too.

    Lando, it IS interesting that a company put the time and expense into this study, you need to utilize all the info they posted. A 90% female ratio would be awesome. I think from seed, a normal ratio is like 60-40.

    mexiblunt Well-Known Member

    So right now I'm slowly bringing my veg hours from 24/0 to 18/6 half hour a day. for some of the reasons posted in this thread and also because with the 24/0 my humidity runs 30%-40%. I'm down to 2 hours off right now and it brings the hum up to 50-65% and slowly goes down during lights on, which I don't mind as I would like it a little higher then 30%.

    Is this a decent way of changing cycles gradualy or should I just go straight to 18/6?

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