Youthmananswered grow question 2 years ago Depending on how much veg you wanna give to them! If you want add 1-2 weeks of veg, go to 5 gallons, if you want to play and try some scrog, you can go 3 for 3-4 weeks, than 5 gallonsto flowering.
But , my advice, go directy 5 and try some lst :)