PURPOSE: A hardening method for in vitro rose plantlets is provided to facilitate the growth of a root in rose plantlets and increase hardening efficiency. CONSTITUTION: The hardening method for in vitro rose plantlets comprises the steps of: tissue culturing rose plantlets in an MS medium added with 900 to 400 mg/l of NH4NO3, 0.1 to 1.0 mg/l of NAA(alpha-naphthalene acetic acid) and 3g/l of gellan gum for the growth of a root; and transplanting the cultured young root in a vinyl pot filled with assorted soil of perlite and peatmoss, or granular rockwool and perlite in the ratio of 1:1 then hardening it under the shading level of 35 to 90%.
