The ornamental design for a stakingsystem for growingcontainer, as shown and described.
FIG. 1 is a front view showing a staking system for growing container, the rear view being a mirror image thereof;
FIG. 2 is a right side view thereof, the left side view being a mirror image thereof; and,
FIG. 3 is a perspective top front, and left side view thereof.
The broken lines in FIG. 1–3 showing a growing container are for the purpose of illustrating the environment of use of the design and form no part of the claimed design.