Fast technique to sex seedlings

[blowdout2269]

Here’s a good read if your interested:

Old school tricks for early plant sexing

So I’m not the person to talk about old tricks but I really want to hear some ways people sex there plants early.

In it you will find this little tidbit:

Old school tricks for early plant sexing

If you get your plants to the 5th or 6 th node give them 2 days of 12/12 lighting ,3 days for equatorial cultivars then put them back on 18/6 your plants will express sex in a very short preflower session.Speeds things up a couple weeks and they go right back to veg within days.

[Magu]

I agree. Many will show sex at the 5th node. It may be faster to just wait 1 week to see.

[Toker1]

In my humble opinion
Nothing happens fast in the plant world.
Switching to this and back again stuff
Is a personal choice I suppose.
Patience is a virtue, and plants appreciate it.

Now I have some strains you don’t dare veg for more that 3 or 4 weeks or they will grow
Huge.

For Me I just am patient, they always reward
Thar.
Good luck

[Cormoran]

I like to do this, but a week is too long imo. At that point they’re gonna actually start to flower, and you’ll have to spend some time revegging. If they’re big enough, 2-4 days is plenty to stimulate preflower growth without actually starting flower; at 5 days I’ve had trouble with some plants wanting to reveg afterwards. As for the OP, I dunno if you’re gonna get anything out of these plants at 4 weeks from seed. They might have to be a little more mature before they really start showing. Either that, or I just start my plants slow, which is also a possibility… I usually figure about 6 weeks. Might also be that I just can’t see them at that size, and would need a microscope to really check for certain…

[slain]

If they are mature, you can flip them for 3 days and then the males will show after about a week.

[Rhizome]

Interesting comment and I guess I will definitely consider it.

I checked yesterday and several seedling are very very small 3"…while others need in my opinion to be topped.

I have 3 baby plants (2 months old) together with the seedling and I guess I will move these in flower room maybe in 15-20l. I will clone those seedling that are already quite tall ( 8-9" -3/5 nodes) and sex…so I will start to figure it out better what I have and as suggested I will leave other plants to grow until are not big enough for normal cutting and sexing. The ones I will sex I will leave in vege to regrow.
I worked with 8 plants in 6.5l and I am not sure if it is the correct combination ( canopy and grow tent full, but small buds).