1 gallon Pot

how big and tall of a plant can the 1 gallon pot hold?

I've heard its 1 gallon per foot if grown in soil. With a 1 gallon hempy bucket you could do a 2footer

Technically 10+ foot, but most likely 2 foot.

a foot or so is my guess considering experience. But then again I seen someone grow a 16 inch plant in a 16oz party cup

Well, here's a few pics of
a plant growing 12/12 from seed
in a one gallon pot.
LST to keep her canopy even
so she's only 13 1/2" from soil to top
she'd be 18-20" tall if not for
the lst.
She's 68-70 days old, 7 1/2 weeks female.