I grew in a 15 gallon poly last fall using a compost, soil mixture. I had to water that plant maybe once a week when I was finishing her up. Colder temps and 12 hour days made me worry about root issues but nothing happened. For awhile I actually used seedling mats around the pot to warm her roots up a few degrees which seemed to either increase her thirst or it simply evaporated the moisture out of the pot.