Sexing plants in original small pots

Hey guys, I'm new here, been lurking for a while but this is my first post. I'm currently germinating 5 KC brains NL special seeds, after reading some (very negative) reviews of KC I was surprised to find that 4 of them are showing signs of tails .
When they're ready I intend to put them in some 3"/3"/3" plastic pots. My question is, will i be able to make them show signs of sex before transplanting them into bigger pots without stressing out the plants? This would be ideal because of space issues in my wardrobe xD
Thanks in advance (and happy thanksgiving to the americans out there)
Birdy

Well, you have two options.....you can flip them to 12/12, for a week or so,(then switch back to vegging hours) or you can let them grow 4-6 weeks, on 18/6(or anything up to 24/0), and let them show their sex, naturally. How old are they now? Almost all strains show preflowers, just after the first month of veg, except for a few exceptions. Also, that's assuming they are growing well, and not behind schedule.

If you with with 12/12, it's not very stressful, it just wastes some veg time. It all depends on how much of a rush you are in, and how much space you have, in choosing which route to go with. 12/12 is quicker, but not by a whole lot. I'd let 'em go naturally, if you have the space to accomodate them, til you can weed out the males.

You will almost definitely need to transplant them.

they don't start flowering from seed when you change your lights to 12\12, they need a minimum of 4 weeks of veg, and they will do it under 24\0 as well, just slower.

a 250ml or so of soil is far from enough.

if height is less of an issue you can get twox 2liter soda bottles, cut the tops off both, cut the bottom of one and drill 4 drainage holes on the bottom of the other.
fill the one with the drainage holes with soil, water down and add as much soil as needed.
put the other bottles on it and fill it up as well.
now you have a tall and narrow pot that can hold around 3.5 liters of soil.

with that you can (but its far from ideal) veg until sexable.

Thanks a lot for your replies guys, I wasn't aware a plant needed a minimum of 4 weeks veg so I guess I'll be going for the tall pot solution perhaps the 2 litre bottle thing. This 4 weeks veg however has raised another issue for me, I only have 2700k CFL's at the moment and can't find higher CT bulbs anywhere, will this do for a while for vegging? also jawbrodt - They've been germinating for 2 days xD still seeds

You can use 2700K, but you would need a whole lot more of them.

If you want small-ass plant that barely yield anything you can keep 'em in small pots and get them rootbound. This way you will need to water every day or so and they'll keep it short.
Or you could trim them down every week to keep 'em small.

If you'll have a small plant you would need less light.