So just a question out of curiosity I’ve skimmed several forums and couldn’t find the question exactly what I’m asking so I’m going to do that now. I’ve been reading a lot of articles on soil , back-budding along with watching several videos on repotting bonsai in development. Videos on bonsai in development seem to focus on candle pruning or bud selection on pines/conifers. It seems straight forward that deciduous in development really don’t need to be put in bonsai media or at least can be placed in a grow box with pumice or root promoting media. Collected pines/conifers develop good roots when placed in a grow box with substrate. But what about pines or conifers that are still in development from seed or nursery stock, does the tree really benefit from repotting and root pruning for inorganic substrate before it’s 75% complete in growth/development. You’d still obviously wire , prune and pinch/cut buds or shoots. But,does back budding and trunk growth differ between organic and inorganic soils. Which soil media would be a better catalyst for this to occur. It seems obvious that planting in ground and pruning back field grown trees yields large trunks , and controlling roots using a pond basket or tile can help as well. But how can this be done in a pot / does inorganic or organic really matter for growth stage/ which would be better.