I think Aunt Mimosa has outgrown the 19-liter pot, she's currently about 140 cm tall, and she's just 1-2 weeks away from flowering. Should I transplant her into a bigger fabric pot in the next few days to give her roots more room to grow for ensuring the buds' growth later on?

Good morning, I wouldn't touch it... It's healthy, the good size comes from reaching for the sun. If you notice the trunk, it's not that thick for a 1.40m plant, so there's still room in my opinion.

Hello friend, a well-done transplant is never bad, but buddy you are a great grower, whatever you decide will be well done 💚🍀🌱🍀💚

1-2 weeks would give time for roots to colonize new volume before flower.. this would definitely have a positive impact. With 1-2 weeks plus 3+ weeks of growth after flower (if accurately guessing flower phase initiation), that plant has a ton of growth potential left. If the roots are cramped, that will stop/slow growth. If growth has already slowed or stalled out, this will definitely help. I've potted up ~400 times and yet to see a negative effect. Not once have i seen a plant stall out or otherwise slow down. The effect is always positive. No worries. The timing her is perfect, if you really do have 1-2 weeks before flower phase starts. (if it is an apples to apples comparison to changing to 12/12 indoors as far as timing) Also, it's part of my SOP to put up 7-10 days before i change to 12/12 (flower). Roots fill in and make proper use of the added volume. I think that believe is tied to transplanting plants that are in the earth. That involves cutting off 95% of their root system and is incredibly stressful to the plant. Potting up is not the same. This process should incur no damage and should not disturb the rootball when done properly.

I wouldn't transplant, that's too much stress. We currently have a plant (Pink Rozey Auto) outdoors at 144cm in a 19-liter pot. That's perfectly fine. We've also had a feminized Thai in a 19-liter pot over 160cm. The yield was great. I believe that the stress is greater than the potential increase in your yield. I'm curious to see what you decide. :-) 👍

yes go for larger por. 2 Weeks should be enough to let her adapt........wont be a failure, but better to do this earlier, so the roots have more time to develop