The ornamental design for a gardentool handle, as shown and described.
FIG. 1 is a perspective view of a garden tool handle showing my new design,
the broken line showing of the blade being for illustrative purposes only
and forming no part of the claimed design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a top plan view thereof; the bottom plan being a mirror image
thereof; and
FIG. 5 is a left side elevational view thereof, the right side being a
mirror image thereof.