Although, in my defense, it seems like in some threads even the old timers get it wrong.
I have seedlings that are about 5-6wks old. I’d like to identify the fems early for 2 reasons.
I have limited space
I want to reverse some plants for seedstock.
In Maine, it’s hard to reverse and harvest seeds on outdoor plants, unless they’re autos. So my plan is to identify the females from strains I’m interested in, and those will get up-potted and stay indoors where I can control the light cycles and force them into flower at some point.
Here’s a pic of one plant this morning. Is it too early?..or can you tell what it is?
Do I need to take the plants I’m interested in and move them to another room so they can be under 12/12?..is it too soon for them to go under 12/12? Once they “show”, can I put them back under 24/7 or 18/6 and get them back into VEG?
It takes male plants between 3-5 weeks to show sex, and females around 6-8 weeks. It sometimes takes longer for both, but that is the general rule of thumb. You don’t need to change their photoperiod. When a plant is sexually mature, it will usually show its reproductive parts on its own, even under a vegetative light period. In fact, sometimes a plant won’t even flower if it’s not sexually mature yet, even if you do switch the photoperiod. Each genetics are different, and there may be devations to all of this, but in the general sense, you don’t need to do anything but wait to discover the sex. In your case, it is still too early.
A few questions:
What made you choose a photoperiod of 24h?
How man weeks from seed have they been under this light?
What kind of light/intensity?
And, to answer some of your questions:
You don’t need to change the light period to determine sex in most cases, provided it’s been growing long enough (see my question above).
It’s never too soon to go under 12/12, but it may take several extra weeks to become sexually mature, before you see anything, just as you would under a vegetative light period. I currently have a plant that I switched to 12/12 after 4 weeks, and nearly 2 weeks later, I still don’t see any stigmas (white hairs denoting the female sex), because it is not close enough to the window of female maturity.
If you switch from a bloom photoperiod back to a vegetative one, it will take a couple of weeks at least for it to ‘re-veg’. The change in photoperiod to bloom caused a hormonal shift, and it takes a lot of energy to switch out of this (because it doesn’t normally happen in nature).
Plants will take longer to show sex under 24 hour light from my experience. Also, that pic doesn’t look like it’s showing male or female yet but my eyes are pretty shit.
Run 18-6 for faster sexing. 24 hours for the start when they are for about 2 weeks and then down to 18-6.
Also, I am in southern Ontario Canada and makes seeds with my outdoor all the time so you should be able to get seed that is finished, cultivar dependent that is. Yiu could also light dep them to force them to finish earlier.
Howdy @Lobstah, while it is possible to observe sexual maturity in veg, it’s going to take the longest to do so under 24 hours of continual light and some might not even show under that light regime. Usually the plants that show under veg show more quickly under lighting that’s closer to 18 hours on, 6 hours off. My preference for veg has been 20 hours on and 4 hours off then bumping it down to 18/6 when nearing when wanting to flip them into flower unless it’s a very long flowering type, but that’s not because I try to identify sexual maturity sooner while in veg, it’s just because that’s my preferred veg technique.
Some plants and genetics that get root bound in veg will start to show sexual maturity quicker than not getting root bound, but I don’t think that’s an ideal way to observe sexual maturity earlier either.
I think the best way if you’re looking to establish sexual orientation quickly if you have the space and resources is to take cuttings as soon as you can and get them rooted. At this point you can put the donor plants that have more established growth into flowering to determine sex and use the cuttings to continue vegging, grow to your ideal size in veg before using them in the ways you want. You can also do vice versa and put the rooted cuttings into flower to determine sexual identification while keeping the donor plants in veg to continue growing and vegging to your ideal size before using them in the ways you want. Those subtle nuances I think are determined by time available and the size of plants you intend to utilize in your projects.
If small plants are used to flip quick to determine sexual identification, if it’s a female it might not be big enough to use in your project but if it’s a male and your project isn’t massive and you’re utilizing the males you’ll probably have enough pollen to use in your project even if using small plants to quickly determine sexual identification. Since you’re doing a reversal project this doesn’t necessarily apply to you but I think it’s still helpful context to consider.
Personally, I don’t like flipping something then revegging unless it’s a last resort or the only strategy available to employ. Especially if they’re male plants because some don’t ever really stop throwing male reproductive parts even when put back into veg, and some will actually begin senescence at some point and stop growing. Many will reveg fine though, again I know this isn’t really an aspect that applies to your project of reversing but I think it’s important context to consider.
Many females will reveg just fine, but it comes at a time delay cost that I think outweighs doing it in the way I mention above by taking cuttings and flipping either the rooted cuttings or the donor plants to establish sexual maturity while leaving the other in veg to continue growing until sexual maturity of the plant flipped is determined and the plant in veg grows to your idealized size without having to go through the process of revegging. Hope this helps. Many blessings and much love
Thanks for the responses.
When I started growing several years ago, I didn’t have a timer, so they went 24/7. Seedlings did very well, so basically stuck with it since then. I did purchase a timer, which I just set up for 20/4. These plants have been under 24/7 since day 1.
I tried to produce some seeds last season by reversing a few branches on a couple of plants. They produced male flowers, but not in time to actually impregnate female flowers and ripen seeds.
So my thinking is this year, I want to identify the females I want to reverse earlier in the season. I don’t care about size really. So I’ll keep them indoors, wait for them to reach a certain height, then put them under 12/12, probably 1 July. That should give them plenty of time to produce polen.
And some just refuse to show sex untl it reaches the 16 or 15 hour mark or lower. Last year I veged a plant indoor over the winter for 16 weeks before moving it outdoor for another 15 or so weeks, and it didn’t push out stigmas until the daylight hours were close to 14.
Howdy @resimax, I didn’t mean it as a hard and fast rule, but more along the lines of plants that do show sexual maturity in veg will usually do so in light photoperiods that are closer to flowering than closer to veg. So to say, if one is wanting to identify sexual maturity in veg, they will have better odds at success with veg photoperiods closer to 12/12 than closer to 24/0.
As you mention, you have a plant that’s 13 weeks and still not showing, which highlights the fact that many plants won’t show sexual maturity outside of flowering. There are definitely subtle nuances to the tipping points of veg and flower with respect to various genetics and their ancestry. Some long flowering types don’t seem to show sexual maturity based on photoperiod at all and it’s more about the time duration they are growing, some it’s about light spectrum and temperature. Sometimes it’s a combination of many variables. Many blessings and much love
Another thing I like to do to get them to show sex fast is take a nice cut and put it into 12/12 in a cup of water with light flower nutes. Yiu will know within a couple weeks
Beautiful well thought out answers
I just wanted to point out in this day and age we have another option.
Spend the 30$(after shipping) on a sext test.
But yeah, with a stubborn plant, just take a small cutting and root it out into a solo cup, under a photoperiod closer to 12. It will show sex soon when it gets root bound. Sure it takes a couple weeks minimum, but it may be more time economical if the mother never would have shown sex yet, and you’d have preferred for her to veg longer (or kept as a mother indefinitely).
