You do need to be careful here. I've killed many small plants by potting up this late in the season.

Part of the answer is to guess accurately that the season will allow continued growth, and that going to a somewhat larger size will work. Definitely do not bump up into a much larger size. You will lose the plant then because the soil will not only be too cool, but it will remain wet with the same water for long periods.

Some species are better than others. Salvia sinaloensis definitely is a plant that likes dry and warm soil and does not mind being a bit potbound.

When you go to pot up the plant, make sure there are a lot of solid white to near white roots. See:
http://www.eclectasy.com/gallery_of_salvias/Newroots1.jpg

Here is a link that might be useful: {{gwi:1244931}}

Rich thank you so much for jumping in here. So far, they are all ok in the 3 inch pots with no roots coming through yet but I wanted to be prepared ahead of time and not wait until I see roots entangled on the outside of the pots. I am trying to keep them in a somewhat cooler room so that they aren't growing too quickly. In fact they were all sheltered on the porch until our temps hit the 30 degree mark for 3 days last week. Thank you also for the link.

Penny