The "Garden Fort" - A GW Project for Children
I loved building forts out of large cardboard boxes as a kid. When we moved, as we did a lot, the large moving boxes we had left over after settling in were put to fun uses, from spaceships to submarines to frontier forts.
Here's a idea for a different fort, to teach your children to garden with fun.
Looking at the frame in the second link, I imagine it would be easy for any Green Wizard parent (or favored relative) to build a similar frame. While it would take most of the Summer to get the plants to fully enclose the frame, it would be a great way to introduce children to gardening and other Green Wizard principles.