Pot size?

I'm growing outside but wanted to do my plants in a pot until I sex them. What size pot should I use that will let the plants get big enough for sexing? How long till I can sex? Thank you all.

Its better referred as flowering or budding, and flowering/sexing your plant is entirely up to you , what kind of training your going to apply to your plants what kind of yield are you after etc, a 5 gal plant would be good for 4-6 weeks veg ,15-20 gal for 8-12 weeks veg, if your going to go thru the whole summer you should put em in 25-50 gal pots/fabric pots