A wallboard joint compound package is provided, including a container defining an interior space and configured for being sealed, a first component of ready-mixed joint compound being disposed in the interior space to a level which leaves a pre-determined head space, and an upper surface of the component is defined in the container. A second component is provided, including water, and is placed in the interior space upon the upper surface, such that the first and second components remain substantially distinct prior to opening of the container.