It depends a lot on how big they are and how you''re growing them, but here's some general information-

I always repot when getting new gesneriad plants. The mix used by whoever had them before might not work for me, and most gesneriads are stimulared to new growth by repotting, not set back, even when roots are trimmed.

Streps like an open airy mix: 1/3 peat moss (or coconut coir or chopped sphagnum); 1/3 vermiculite; 1/3 perlite. It's especially important where it will be hot and humid to keep lots of air around the roots. Clay pots might even be a good idea over there in NJ, especially in summer, though that can make repotting a little harder later.

If the roots have completely filled their cups, and the leaves are so big they're tipping over, a 3" pot would be fine. I wouldn't put them in anything bigger until they get crowded and start drying out too often to keep up with. They really don't need a lot of soil mix around the roots; just enough to keep them anchored and some moisture around them. Unused, "dead" soil around the roots can encourage rotting.

We had a bad experience with coconut coir, so I personally would keep away from it - and I usually add another 25% of coarse perlite to the 1:1:1 mix and a layer of coarse perlite on the bottom to increase the air access to the roots.

When you repot them be sure that you keep them potted no deeper than they were before, they should sit on the top of the mound- like the king of the hill.

My limit for streps is normally 3" for "mini streps", 4" pot for regular, 5 for Xlarge broad leaved varieties.

I put wicks in the pots - but actually bottom water them. They need to be dry before you water them again. Wicks help to rewet them. I keep 5 pots in a black tray - and water the whole tray with a 1/2 inch water after all of them dried up and ready to start drooping. This dry time keeps from getting root rot. But that's fior mature plants - you will need less water.

Dirtmonkey is right to point towards clay pots. I heard that people who do not have basements - the clay pots are the summer survival trick fore the strep growers they fill the space between the walls of smaller plastic pot with a strep - and larger clay pot with wet sphagnum moss - and it cools the roots - thanks to the evaporation through the pores in the clay.

And to add to Dirtmonkey ideas on how to keep them from tipping after you repot - use bamboo skewers to prop them, bobby pins to pin the rootball and if the leaf is so heavy - that nothing else helps - trim the leaf in half. It wouldn't harm the plant - and you can put the tip for rooting.

i.