I grow just about everything in containers. Being in Zone 10B, I don't have to worry about wintering, but the containers better let me control the soil and nutrients. If your trees were not fruiting in the containers, it's possible that you were giving them too much Nitrogen which will cause a lot of foliage, but inhibit fruit growth. If you still have that BT in a container, I'd try cutting back the Nitrogen and upping the Phosphorous and Potassium, along with making sure they have a full suite of micro-nutrients (I add rock dust to the soil mix) and see what happens.