Greenhouse growing

My greenhouse isn't going to be very big, there for I am limited to growing space. My question is: If I use small pots will it deplete my plants in any way? Or is there a better technique to keeping plants small.

Roots grow as much as they can, I've seen a grow in Cali on Youtube with six foot BUSHES, mainly cause some of them were planted in 36 gallon trash cans with super soil and room to grow roots.
Also, you could flower early....prune...train...I'm sure the list goes on.
I'm guessing your somewhere it's legal, cause I don't see the point in a guerilla greenhouse.... but I'm sure there could be some perks

Well I'm up north looking for a few extra weeks for my sativa strains to finish, that's where the greenhouse comes in. But its only going to be 8x6x6.

no matter when you start your sativas they are going to start to flower in the same time you dont wanna start them to early cause they will stretch far beyond what you think so calculate what size you want them and plan ahead i started some indica dominate strains in july and they got almost 3 feet sativas could easily finish at 5 feet if i would plant a lil earlier