Have you aerated them? I got root bound issues last year, in 3 gallon plastic pots , so now I take an ice pick to them. Seems to help I also went up to 10 gallon fabric and having had root bound issues before , I don't forsee the issue causing a problem as with a fabric pot as the roots can technically escape better.

I did transplant one once that I thought had the issue to outside in ground at about the time frame you are at , and she revegged on me .

I'm curious what has you thinking you're running out of root space in those 5 gallon pots? It could be the pictures but I don't see any sign of leaf issues that might suggest restrictions in the soil region.

Southern Ontario weather likely means you'll be hitting the dew point every night come September. If you place these plants in the ground, you won't be able to move them to keep them dry. Too many people think that they are good growing outside up until the first heavy frost. It doesn't work that way with cannabis. The nightly dip into the dew point will be a potential issue. You may want to reconsider placing them in the ground so you can move them out of the weather so they have time to mature. Otherwise, you will have your hands full come September and the wet humid nights it brings.

Anyway, lets hear more about your situation and what options you have. Fall weather can damage your crop long before the first frost arrives.

They should grow in 5 gallon fabric pots. It just might not get as big as a 10 gallon pot and so on. I used to grow in 5 gallon.

The roots will grow out of them sometimes. I had some that did. They got.through the fabric and was drinking from a runoff tray.