@@weshgato, depends how much You want. Now, I am growing in 1l Air Pots and 15g from one pot can be done. Year before, I grow in 3l Air Pots and also have about 20g from one pot. What does matter is health and density of buds. So if You are looking for about 20g from one plant, 2l is good, but need to be healthy plants with lot of light.
@Cannabud, friend...very little...I do not have good scales for that...I think like 15g wet/5g dry...I am drying the second one...it looks very same...