They also give good practice re-potting seriously root-bound plants. I unwind roots, but I'm still timid about root-pruning.
I got a n ic e big lavender plant that they couldn't kill by under-watering no matter how hard they tried. I think it finally put on a show of looking pouty and unhappy so they would mark it down and someone would give it a better home.
Haunting those clearance racks at end-of-season also gives me an excuse to keep watching like a hawk for when they give away empty pots and web trays at the end of the season. Sometimes BIG pots, and often large numbers of matching 4" pots.
