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So technically I think it might fit under Edible Ammunition. "...any type of food used as ammo, whether it be thrown..."
If it could be differentiated out, it might stand on its own. Could also be a sub-trope.
In either case, since we don't have exploding crops in real life, it could also be a form of Fantastic Fruits and Vegetables.
Seconding Fantastic Fruits and Vegetables, but regarding exploding fruit: while the explosion isn't of the combustion sort...
Might be a viable subtrope if it isn't Too Rare to Trope.
Edited by Scorpion451Seconding Edible Ammunition. I don't think this would inherently fit Fantastic Fruits and Vegetables though, since it could refer to a bomb that's designed to look like, but isn't actually, a fruit or vegetable. The example might, however, from what is said here.
LP Deprecation Cleanup | Ask me about SMP LiveFantastic Fruits and Vegetables would fit all the exploding and projectile plants in the Plants vs. Zombies game, I'd say.
To clarify, since exploding vegetables aren't a thing in a real life (outside of some crazy accidental scenarios), they'd be Fantastic Fruits and Vegetables. Since they are used as weapons for their explosive capabilities, they're also Edible Ammunition.
So, they're Fantastic Fruits and Vegetables because they explode, and because they explode, they're used as Edible Ammunition. They fit both.

I've noticed in two different video games the idea that you can grow explosive vegetables for use (Dodge That Anvil and Legend of Zelda: Ocarina of Time). In both games, as soon as you pick the veggie the fuse is lit, so the primary weakness of these home grown explosives is that there might not be one where you need an explosion. On the bright side, they don't deplete your bomb count. More standard explosives lets you set the fuse wherever you want. Is this concept prevalent enough to be a trope? If so, is it already one by some name that googling "vegetable bomb" doesn't return?