A method for cultivating leafy vegetables that can reduce the production cost by efficiently irradiating the leafy vegetables with the light necessary for growth, and that can produce leafy vegetables with high commercial value, and its cultivation Provided is a light source device for growing leafy vegetables for use in the method. A leaf stem vegetable growing method for cultivating leaf stem vegetables by irradiating light, and suppressing the growth of the stem at the top of the stem at least at the initial stage of growth when the stem and the leaf can be distinguished A stem growth suppression period for irradiating light from a stem growth suppression light source having a high blue component is provided.生育に必要な光を効率よく葉茎菜類に照射することで生産コストの低減を図るとともに、商品価値の高い葉茎菜類を生産することが可能な葉茎菜類の育成方法およびその育成方法に使用する葉茎菜類育成用光源装置を提供する。 光を照射して葉茎菜類を育成する葉茎菜類育成方法であって、茎部と葉部とが区別できる少なくとも生長初期時期に、茎部の頂部に、茎部の生長を抑制する青色成分の高い茎部生長抑制光源からの光を照射する茎部生長抑制期間を設ける。
