Abstract: A concrete construction block is formed with a large cavity toward the exterior side of the wall of which it becomes part. The cavity, or protrusion, is shaped to extend outward at the top but angled or recessed back at the bottom to coincide with the foremost edge of the block's rectangular bottom. The cavity may be shaped in any of several ways but the top portion extends forward more or less in the manner of a flowerpot so it may be filed with soil to support plants planted therein. Drainage is provided so that water descending from one block flows into the plant bed of a block below. A large number of these planter-blocks economically provide a cooling effect upon the building's interior for scientifically established reasons related to botanical function of the plants.