Abstract:In order to clarify the effects of different culture periods on the growth and root distrubution of Platycladus orientalis seedling, we cultured seedlings directly seeded in Seed-bases buried in culture groove in March, and seedlings seeded at the same time in Seed-bases which were put on a net first, and then transplanted in culture groove in June, August and October (intituled as Seed-base seedling, Jun transplanted seedling, Aug transplanted seedling and Oct transplanted seedling, respectively). The growth of seedlings were investigated and roots were dug out in the next March for root surveying. The results showed that seedling height, maximal root depth, dry weight of root and shoot decreased as the fllowing order: Jun transplanted seedling > Aug transplanted seedling > Seed-base seedling> October transplanting seedlings. Root-shoot ratio decreased as the fllowing order: Jun transplanted seedling > Aug transplanted seedling > Oct transplanted seedling > Seed-base seedling. As the increasing of Seed-base culture time on net, the growth of main root was limited, and the taproot-lateral root length ratio was decreased because of air root-pruning. However, root roping phenomenon did not appear at any culture periods in this study, and the taproot regrowth after transplantation was not damaged.