Your plants need food....but not just any food. Nutrients that have the wrong ratio of N-P-K can actually retard bud growth. You want something very very low in N, higher P, with the K somewhere in the middle. Most commercial fertilizers have way too much N for proper flowering of cannabis. I really recommend getting somerthing right away formulated for cannabis. If you do not have anything locally, you need to order it online. A plant that is not fed will not thrive. I am quite sure that you probably have multiple nutrient deficiencies.
NEVER put more than 1 plant in a single container. Also do not start seeds in a large container like a 5 gal--this actually impedes good root growth as it is hard to get the water and nutrients where they need to go and to make sure they are getting the correct amount of everything.
You are not going to want to go larger than a 5 gal bucket with a plant that size.