[PROBLEMS] To increase fruit body yield and high commercial value, i.e., a child, in mushroom cultivation, in particular, cultivation using a mushroom cultivation medium based on common sawdust such as oak and kunugi. Provide a means by which mushrooms with large entity size or good quality can be harvested. A mushroom cultivation medium additive containing an aqueous extract of a willow, a mushroom cultivation medium added with an aqueous extract of a willow, and a fungus that cultivates an inoculum of a mushroom in a medium added with an aqueous extract of a willow The present invention relates to a method for cultivating mushrooms, including a floor culture step and a generation step for generating mushroom fruit bodies. [Selection] Figure 1【課題】キノコの栽培、特にナラやクヌギ等の一般的なおが粉を木質基材とするキノコ栽培用培地を用いた栽培において、子実体収量を増加させる、さらには商品価値の高い、すなわち子実体のサイズが大きい又は品質の良好なキノコを収穫することができる手段を提供する。【解決手段】ヤナギの水性抽出物を含有するキノコ栽培用培地添加剤、ヤナギの水性抽出物を添加したキノコ栽培用培地、並びにヤナギの水性抽出物を添加した培地でキノコの種菌を培養する菌床培養工程及びキノコの子実体を発生させる発生工程を包含する、キノコ栽培方法に関する。【選択図】図１
