We claim the ornamental design for a closed top planter bag, as shown.
FIG. 1 is a front perspective view of the closed top planter bag showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is rear view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken lines showing are included for the purpose of illustrating of portions of the closed top planter bag and form no part of the claimed design.