You could use an empty milk jug as a pot just make sure to put holes in the bottom for drainage and oxygen and cover the outside of the jug with duct tape or something else so that it is light tight plant roots don't want to stare at your lights all day, they don;t like that. As far as picking the buds technically you can do it as soon as they start but you should wait until they are gettign ready atleast 7-8 weeks into flowering depending on the strain. You should however wait until they are fully ready to harvest and then harvest the whole plant at once and then dry and cure them, which will take you another 2weeks-2months or so. The drying and curing process is often overlooked, but after spending all of that time and care on your beauties you need to treat them well for a good tasting smoth finish.