2' * 2' should be just enough for 2 small/medium sized plants.
The flours will be enough for the first weeks, I would suggest you veg them for roughly a month.
Then I would suggest moving to a 250w HPS lamp for the flowering period.
You MUST take into consideration that you'll need quite a lot of ventilation even for a 250w lamp, if the door to the room is going to be closed.