pot size

ive got a 2mx2mx2m tent i was thinking of putting 25 plants in what size pots should i use are 15l too small
i was thinking of doing a sea of green with about 40 plants in but think il go with the 25 but dont want to restrict them putting them in pots too small
thanks

15ltrs are a reasonable size but its going to come down to how long you are vegging for. That's only 6 plants per m2(assuming your using all space) so you can afford to veg them for 6+ weeks and 15ltr would allow that. Still 18ltr would make sure your not struggling and has roughly the same base size as the 15ltr pot so would fit. Don't forget to think about how you are going to get in there and water them. I used to have a 2mx2m and i kept one meter square for easy of movement when watering and somewhere to sit with reasonable comfort when harvest day comes.