depends on how how big of pots you are using, if your going to veg for a month transplant from small pot into 1gal or 2gal pot after a couple weeks, then transplant into 4gal or 5gal pot right before flowering. just what i do man.
the longer you veg the bigger the plant
the bigger the plant the bigger pot you'll need
jus a few pics so u know how it works for me