Abstract: A plant-holding type window box has wedge-tight spring-lock assembly-securance system providing rapid, tool-less set-up for use and knockdown for shipping or storage; plural hangers incrementally adjust in pre-spaced holes and screw-adjust in depth in coaction with screw adjustable stand-offs to mount the unit securely to all usual building-structure configurations; conveniently large and accessible assembly wedges so-relate visually to the wall members that the wall structure as a whole appears unitary when assembled; economical straight-cut fabrication is employed throughout to hold all edges of two-level plant pot holding structure.