What are you using as a medium? I use 100% perlite and hydro nutes pHed to 6.0. Water when the reservoir in the bottom of the pot dries out. I usually pick up the pot and through experience, you'll be able to tell right away if it needs water. You could grow entirely with a 44oz cup depending on how big you want the plant to get. Generally, roots aren't as restricted in hempy buckets as soil, so you can grow bigger plants with smaller pots.