I've grown edibles for years in my back yard, but never saw many snakes until I started putting out my birdfeeders. The birds spill a lot of seeds on the ground, which attracts mice and rats at night - which in turn attracts the snakes. I'm lucky, my snakes are non-venomous Southern black racers so far. They're big, fast and beautiful and also very timid so as soon as any person, or even my cat comes out they vanish.
The pond itself is attractive to snakes as they also hunt frogs and maybe even birds that are in or near the pond. So, as Angie says, better to educate your child about the snakes in any case. They are there, and could certainly come to your garden but planting the garden shouldn't attract them.
