Generally in soil, you should not be in a container bigger than the plant. If the plant is the right size in a 3 gallon pot, you will initially water once every 4-7 days depending on variables. As the plant gets bigger, the watering will be more frequent. Once you have to water every 3 days its time to transplant or you better be finishing. When attempting to finish in a 3 gallon pot, you will get to a point of daily watering or watering every other day, again depending on variables. Personally, i know this because i do it all too often. Starter plugs>solos>1 gallons>3 gallons in a 2 light rotation, harvesting every 65-70 days. Cheers