A safety gate has a frame with top and bottom assemblies spaced apart in a vertical direction and with opposed side assemblies spaced apart in a horizontal direction in a deployed configuration. A length of the top and bottom assemblies is extendable and retractable to adjust a width of the frame between the opposed side assemblies. A flexible barrier is connected to and supported by the frame. A one-way jack mechanism is carried on each of the top and bottom assemblies. The length of the top and bottom assemblies can be extended without actuating the jack mechanisms to adjust the frame to a desired width to loosely fit a space between two surfaces. The one-way jack mechanisms, when actuated, incrementally further extend the length of the top and bottom assemblies such that the frame interferingly fits between the two surfaces under compression.