A cultivation method is provided, whereby a cluster of brown beech mushrooms (Hypsizygus tessellatus) does not break apart after a hard tip part is cut off, and whereby a cluster without a hard tip part can be harvested. A cap for a cultivation bottle for brown beech mushrooms comprises a cylindrical member 20 that is fitted onto a wide-mouth part 54 of a cultivation bottle 50. The cylindrical member 20 includes: a large-diameter cylindrical part 22 that covers and is fitted to an end edge of the wide-mouth part 54 and an outer surface in the vicinity of the end edge； a small-diameter cylindrical part 24 that has a first opening 21 with a smaller diameter than the large-diameter cylindrical part 22, and that is positioned toward a center of the large-diameter cylindrical part 22； and a connecting part 25 that connects an outer surface edge of the large-diameter cylindrical part 22 with the small-diameter cylindrical part 24. The height of an inner surface 15 of the small-diameter cylindrical part 24 is between 6 mm and 30 mm.本發明之課題係揭示一種即便將蒂頭部分切斷，蕈菇亦不會四散，而可收穫無蒂頭之株狀鴻喜菇之栽培方法。 本發明之解決手段係一種鴻喜菇栽培瓶蓋，其具有嵌合於栽培瓶廣口部之筒狀構件；其中前述筒狀構件具有：大徑筒部，係覆蓋嵌合於前述廣口部端緣及該端緣附近的外側面；小徑筒部，位於中心側且具有徑長比該大徑筒部還小之第1開口部；及連結部，連結前述大徑筒部外周緣與前述小徑筒部；且前述小徑筒部內側面之高度為6mm以上且30mm以下。
