The ornamental design for the planting pot tray, as shown and described.
FIG. 1 is a perspective view of a planting pot tray in accordance with the present invention showing the design in an environment of use with planting pots;
FIG. 2 is a top perspective view of the planting pot tray;
FIG. 3 is a bottom perspective view of the planting pot tray of FIG. 2;
FIG. 4 is a side elevation view of the planting pot tray of FIG. 2;
FIG. 5 is a front elevation view of the planting pot tray of FIG. 2; and,
FIG. 6 is a top elevation view of the planting pot tray of FIG. 2.
The broken lines are for illustrative purposes only and form no part of the claimed design.