Sexing at germination

BigBudBalls said:

But then 24/0 light will make them plants more male. etc.
(of course thats the battle between genetics vs. environment debate. I still feel environment makes a hermie, genetics is core sex)

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that's a dutch passion misprint. 24/0 produces more females, dark cycles encourage males.

in my experience the main factor for affecting gender is temperature (cold = female, hot = male).

kp

kindprincess said:

in my experience the main factor for affecting gender is temperature (cold = female, hot = male).

kp

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From what point? Growing from seed you are suppose to keep the seed in a warm, humid environment at least until it sprouts (I keep mine under the humidity dome for about 3 days after they break the surface).

So at what point do you believe the temp should be lowered to a cooler temp. to encourage female? One week? Two weeks? As soon as they break the surface???

What's your experience been?

Everything I've read seems to indicate that temperature will not affect chromosomes and phenotypic expression. Unfortunately, there is such a wide variability in plant species, and we don't permit much marijuana research (despite its being a top cash crop) so it's left to a lot of anecdotal evidence.

my area is relative to the outside temperature. i can keep it within range, but during the winter my veg room is 56-62f. in the sumer it's 65-80f. i have a hard time producing males in the winter. the plants grow slower in the cooler temps, but they do thrive, and do well.

things i've found produced more females:

cool spec for veg. i like to use a mix of warm and cool, but blue light has resulted in 100% female ratios for months at a time (starting ten seeds every week) when combined with the cooler temps.

cooler temps; described above

high nitrogen, little to no phosphorous. phosphorous seems to help produce males.

i've done the seed selection chart thing, and disproved it for fact. of five "male" seeds and five "female" seeds, i got ten females.

stress can help produce males; some of my most tortured seedlings will often be male, but reverse to female in flower.

hope this helps.

kp

Kind Princess, that's interestimg research. Not what I really wanted to hear though as I am struggling to keep my 3 week olds below 80f, for the most part the temp has been around 72/74 most of the time. I will be keeping my fingers crossed.

my outdoor plants are in 100f+ every day..... you'll be fine, i'm sure. constant temps are what i based my post, so a freak warm spell is not the same. hope you get all girls

well...here is an update...I have been keeping them under cfls for 24-0...I just moved them under my 600 watt hps for the night and will set them up under my 150 in the morning.....they are lookin good so far...2 has the entire seed pod still covering all the leaves so that's why it looks odd in the pics....

kindprincess said:

my area is relative to the outside temperature. i can keep it within range, but during the winter my veg room is 56-62f. in the sumer it's 65-80f. i have a hard time producing males in the winter. the plants grow slower in the cooler temps, but they do thrive, and do well.

things i've found produced more females:

cool spec for veg. i like to use a mix of warm and cool, but blue light has resulted in 100% female ratios for months at a time (starting ten seeds every week) when combined with the cooler temps.

cooler temps; described above

high nitrogen, little to no phosphorous. phosphorous seems to help produce males.

i've done the seed selection chart thing, and disproved it for fact. of five "male" seeds and five "female" seeds, i got ten females.

stress can help produce males; some of my most tortured seedlings will often be male, but reverse to female in flower.

hope this helps.

kp

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Since there is so little research or published factual information on this stuff, have you kept any records to help the data sets? As I understand you, warmer temps seem to cause more female expression, yes? But you're growing exclusively indoors, correct? Have you done any outdoor growing and seen any temperature influencing ratios in the same manner?

hey guys whats the update

kindprincess said:

my outdoor plants are in 100f+ every day..... you'll be fine, i'm sure. constant temps are what i based my post, so a freak warm spell is not the same. hope you get all girls

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I have a quick question about feminized seed. I just planted 2 feminized seeds from a seed bank...I have a grow box but it is outside on my back patio...the temp gets between 80-100 during the sumer time in the box...I have it well vented with alot of fans blowing on them..Can the high temps turn my Feminized seeds male??

I'm germinating a few seeds at the moment, so far one of them has curled over itself. The rest are yet to shoot roots.
I'll keep you updated Angus.
This is interesting.
Be great if it turned out to be true.
That way people wont have to put time and effort into plants just to find out they are useless.

Thanks for starting this thread.

Seamaiden said:

Since there is so little research or published factual information on this stuff, have you kept any records to help the data sets? As I understand you, warmer temps seem to cause more female expression, yes? But you're growing exclusively indoors, correct? Have you done any outdoor growing and seen any temperature influencing ratios in the same manner?

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no; cooler = more females warmer = more males.

i should probably say that even with a "higher male count in the summer" i still have a hard time producing them. temps seem to be the main contributing factor, but the others play a part too...

my outdoor plants are usually 50/50-75/25 female/male. they get massive quantities of stress during july/august....

as for records... i'm writing a book (three, actually)

deesbarrett said:

I have a quick question about feminized seed. I just planted 2 feminized seeds from a seed bank...I have a grow box but it is outside on my back patio...the temp gets between 80-100 during the sumer time in the box...I have it well vented with alot of fans blowing on them..Can the high temps turn my Feminized seeds male??

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fem seeds can, and often DO go male. too much stress, and it can happen, along with herm issues.... more likely the plants have become acclimated to the weather over the course of the last several weeks, and are not as stressed as you might think.

my outdoor plants get full sun, dawn to dusk..... try standing outside for 20 mins without getting a sunburn, and you'll understand what they go through . watering is a daily if not twice daily job....

i like to give credit to the veteran growers. i would love to assume that if it's not a KNOWN trick of the trade, there's probably a reason. if this root tail thing worked (which we know through science that the taps will grow however they want, sporadic) then it'd be as common knowledge as 12/12 lighting times for flower. the good stuf sticks, the bs is always "new".

just sayin.... don't get your hopes up

kp

deesbarrett said:

I have a quick question about feminized seed. I just planted 2 feminized seeds from a seed bank...I have a grow box but it is outside on my back patio...the temp gets between 80-100 during the sumer time in the box...I have it well vented with alot of fans blowing on them..Can the high temps turn my Feminized seeds male??

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Plants are either male, female or hermaphrodite. The fem seeds won't turn male - they will either be male or female and stress can cause the hermaphrodite condition.

i use a lot of fem seeds and my experience (anecdote) is opposite conventional wisdom. Under the same conditions (in the same reservoir) - regular seed bank seeds (not feminised) turned hermie and the fem seeds stayed true female under heat stress conditions.

kindprincess said:

i like to give credit to the veteran growers. i would love to assume that if it's not a KNOWN trick of the trade, there's probably a reason. if this root tail thing worked (which we know through science that the taps will grow however they want, sporadic) then it'd be as common knowledge as 12/12 lighting times for flower. the good stuf sticks, the bs is always "new".

just sayin.... don't get your hopes up

kp

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Thats pretty much why i stopped posting....

I figure, if this was a fact, it wouldnt become "grondbreaking" science on RIU (no offense to RIU, anything i dont know is groundbreaking when i see it here)... but ive been reading my girls botany book, and i still havent found anything to support the theory...

Like KP said, it would be common knowledge like 12/12 for flower, or the paper towel method to germ...

All im saying is science has made more strides than we can possibly comprehend... plants have been growing for millions of years, we've been studying them for thousands, its very improbable that this holds any factuality given the research done thus far...

But im no scientist, what would i know... i just love reefa...

I agree with you guys...there is no supporting evidence...but hell...the way I see it is we are all growing anyway so why dont we track everything we can...it's not like the govt is gonna do it for us ya know. either way whether we had this thread or not we are all still planting seeds on a regular basis...so grow on growas

kindprincess said:

no; cooler = more females warmer = more males.

i should probably say that even with a "higher male count in the summer" i still have a hard time producing them. temps seem to be the main contributing factor, but the others play a part too...

my outdoor plants are usually 50/50-75/25 female/male. they get massive quantities of stress during july/august....

as for records... i'm writing a book (three, actually)

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Mind if I pick your brain a little further, then? I have more questions on this temperature bit, which I find fascinating because it's already well known and documented in the animal world (crocodilians, for instance).

First question is; If temperature affects sexual expression, then are we talking about a cumulative effect, or temps during a specific phase of growth? I'm hoping I'm asking the question in a way that makes sense.

What I mean is this, and I'll use my first grow here as an example; I started my unknown variety back in April. They were exposed to several frosts, which did them no real harm but did seem to delay growth. Now, it's been quite warm the past couple of weeks. However, to this point the majority of their growing period has been in cooler temperatures with the exception of one hot week during May when they were still seedlings.

Now I'm starting some known strains, and it's definitely been warm (although the past couple of days have cooled off perfectly). So, they're showing better vegetative growth (again, still just seedlings getting their 2nd set of leaves). However, there's one strain, Papaya, of which I could only get two seeds to germinate and only one actually sprouted.
Based on your experience, can you make a guess as to the male-female ratios I might expect from each batch?

Do these questions make sense?

Also, I've done work as a book editor (I would have sent this via pm, but cannot). If you're in need of proofing I am very good at it. I can check data sets, definitions, have created an entire glossary of scientific terminology (specific to the book). I do not change the author's work, simply ensure it's understandable and correct (grammatically, spelling, punctuation, and so on). If you're interested just send me a message.

im down for the experiment. will let u know if i can get to flowering (so far in three tries i am 0-3 )

Hi, Just subscribing and throwing in my two cent.

The guy at Nirvana told me plant sex is decided by the growing conditions and the gentics of the mother plant not the growing condtions of the seedlings.

While I am very scepticle of this idea, I don't see why it couldn't be true. Plants show signs of sex long befor flowering. Why not at the seedling stage.

I will of course conduct an experament once I get the chance.