A plant culture box assembly (10) having a box (20) and an upper cover (30). The box (20) includes a bottom portion (21), a first peripheral wall (22), and a fastening portion (23). The first peripheral wall (22) is connected with a peripheral edge of the bottom portion (21), so that an opening (29) is formed between the first peripheral wall (22) and the bottom portion (21). The fastening portion (23) is annularly formed at an external side of the first peripheral wall (22). The upper cover (30) includes a top portion (31) and a second peripheral wall (32). The top portion (31) is mounted to the opening (29). The second peripheral wall (32) is connected with a peripheral edge of the top portion (31) and tightly combined with the fastening portion (23) to enable the first peripheral wall (22), the fastening portion (23), and the second peripheral wall (32) to jointly define an isolated space (40). In this way, the box (20) and the upper cover (30) can have preferable airtight effect therebetween.本發明有關於一種植物培養盒，主要包含有一盒體及一上蓋，盒體具有一底壁與一第一周壁，盒體之第一周壁連接於底壁之周緣而與該底壁之間形成一開口，且盒體之第一周壁設有一定位部，上蓋具有一頂壁及一第二周壁，上蓋之頂壁蓋設於盒體之開口，上蓋之第二周壁連接於頂壁之周緣且與盒體之定位部密合，同時盒體之第一周壁、盒體之定位部，以及上蓋之第二周壁之間形成出一區隔空間，藉此，盒體與上蓋之間能夠形成良好的氣密效果而達到本發明之目的。
