I have seen root expansion with my plant especially from the bottom. It does make a difference because the plant still has a while to go.4 weeks in, you're not gonna see much root expansion going forward. Probably not gonna make any yield difference
Agreed. However, I had a girl once very root bound in a plastic pot (2gallon) that tapered to a smaller diameter at the bottom. Good sized plant yielding about 4oz in the end, I up potted(3gallon also tapered pot) just to help the roots possibly expand and breath so as to help prevent and weird deposits develope. I want to say she was around week 5 of 11. Not sure if it helped exactly but it def didn't hurt her. When I up potted i made sure the soil was damp not soaked and lightly squeezed sides, then i put the pot onto sometime small and round...a rock usually works fine...and push down on the rim. This will USUALLY pop the plant right out of the pot with very little harm, left root ball as is with no breaking it apart or anything but i did dust it with some Azos from Extreme Gardening to help lessen the shock from transplanting.4 weeks in, you're not gonna see much root expansion going forward. Probably not gonna make any yield difference