A vault cover of greenhouses has a first face and a second face. A series of first passage is defined in the first face of the vault and a series of second passage is defined in the second face of the vault cover, wherein the first passages and the second passages are interlaced to one another. Each first passage extends through the vault cover along a woof of the vault cover and each second passage extends through the vault cover along a warp of the vault cover. Consequently, the vault cover can quickly and conveniently form a vault of a greenhouse after a first flexible stick passing each first passage and a second flexible stick extending through each second passage.
