This is for plants vegging, not flowering for five weeks!, but thought it would be info most can use:
When the root ball is fairly dry, palm the soil surface, turn the pot over, and gently let the plant/root ball slide out of the pot. If it's showing a lot of root (root bound) pot it up to a bigger pot. This is the easiest way to determine if a plant needs to be re-potted. I like to re-pot when there is enough root to keep the ball together, not much more. If it is root bound I will cut some of the roots but I don't recommend this to people not experienced at root cutting. It will also slow down the growth for a while. From what I've seen on weed forums a good percentage of people grow root bound plants. They dry out faster, require more nutrients, and stress more.
When re-potting I prewater the plant an hour or so enough to get the ball fairly moist, not heavy wet. This allows the roots to take up enough water until any water absorbing roots can regrow (water absorbing roots grow in a single cell row so are very easily torn). I use something like Super Thrive or a rooting hormone to reduce stress and encourage root repair and growth. A tea a couple of days before is good, also.
When plants are re-potted they usually take a couple of days to get going. Doing it as described above, they will usually take right off.
