it's my first grow and i'm just wondering at what point should i find out the sex of my plants, at the moment they are all around 10 cm tall with about 16 leaves each, should i put them under 12 hours now or wait?
id say plants about double in flowering, not triple. the longer you wait the better, you should do some research about topping and LST cropping because you have a bit of time to have some fun with it before you flower.
wait, if the plant isnt mature before you flower it the plant will force itself to mature, which wastes valuable time and that could have been solid veg growth. if you wait till they have pre-flowers when you flip to 12/12 youll not only have larger plants, it also wont stall out like if you force it to mature, it will start good budding within 3-4 days of 12/12 switch usually.
Depending on your supply/number of plants, I'd wait until you can take a cutting from them. With that, you can nurture the cutting back up, put it in darkness for 36 hours and return it to your garden until it shows its sex. Logic being, why waste a plant if you get lucky?
sounds exciting, do you have relevant threads or places to look for advice on these kind of techniques? all i know about is scrog systems and secondary budding