You don't explore to use the shovel, you click on ingredients in the background, like how you collect mushrooms, raspberries, tomatoes, etc. The only thing youd get from pressing explore is rocks, sticks, and enemy encounters.
Things that can be dug up using the shovel look like green sprouts growing from the ground, plus there are only three locations (that I know of) where you can actually find foragable vegetables (all to the left of the tavern).