At what point do you put your trees into training pots?
That depends what you define as "training pot" and what you want to achieve by "training" the tree. The term is often used when bonsai enthusiasts want to slowly adapt the tree to a really small pot. What you are truly doing is creating an efficient root-mass system; wide, dense, and shallow. So that the tree can live in a very shallow pot. This can be done, anytime you believe your tree is ready for display, and life on a very shallow pot. Usually you already have the desired trunk thickness, branches, and good ramification. Once you start restricting the natural root growth of your tree, it won't grow as freely as it does when wild, so the tree will take longer to change structurally until a dense and efficient root mass system is achieved.
