Ive got various large 14-16" pots going, there's a cherry tom, basil, ichiban eggplant, cubanelle pepper, and pole beans. Usually never get around to trying any mulch in my containers. They are currently mostly 1/2miracle gro,1/2 moisture miracle gro potting mix, and some older potting mix re-used towards the bottom.
-Any easily found/purchased mulch suggestions, or don't mulch etc.?
-Isn't there something about pebbles for things like rosemary, sage, thyme, that like to be dry quicker?
-Would other veg benefit from pebbles?
-Pine bark fines seem like the same texture as the potting mix, so not a good choice?
I would not worry too much about mulching containers, but here are a few possible reasons to mulch:
If you are in a windy location, and the soil dries too fast. Mulch with a fine bark or chips that is OK to mix with the soil at the end of the season, or else a coarser material that you will scrape off before you re-use the soil. Too fine a material will just blow away.
Plants that prefer drier conditions could be mulched with pebbles. Many of these are perennials, so you will not be repotting and reusing the soil as often. Still, make it a pebble size that you can salvage easily when it is time to repot. These will help the soil stay loose and open at the surface for better air/water exchange.
When I grow things in containers I am usually packing things in there so close that I cannot see the soil, anyway, so the plants themselves provide many of the benefits of mulch.