An apparatus for separately storing compostable material in a kitchen waste receptacle has a holder panel with an adjustable releasable attachment for suspending the apparatus in the waste receptacle and a cradle panel connected to the holder panel with a hinge, the cradle panel movable between a first position coplanar with the holder panel and a second position non-coplanar with the holder panel. The cradle panel includes a lock for releasably engaging the holder panel to maintain the cradle panel in the first position. A bag retainer seated in an aperture holds a compost bag, and the bag retainer positions the opening of the compost bag such that the opening is occluded when the cradle panel is in the first position, and the opening is clear when the cradle panel is in the second position.