Number of plants in an 18 gallon rubbermaid

thanks latewood. your knowledge is invaluable

my friend has 2 25 litre buckets 3 plants in each you have to start with fem seeds the stems are around 1.5 inches across at the base after 4 weeks of growth tallest is nearly 2 and a half feet with 16 internodes and the side branches are up to half a inch thick they look like trees and are all sativa, id say just start with fem seeds and get some 25 litre buckets with a lid.