Ellion's Roasted Chestnuts

You are able to cast a spell on four simple chestnuts, or acorns, or any other large nut.  You imbue the nuts with a mote of fire, and the nuts will contain the mote for as long as you concentrate upon the spell.  As soon as you release your concentration, each nut will erupt in a small fiery explosion that will do 1d6 fire damage to anyone, or anything that is flammable, within 5 feet.  The nuts will only explode when you remove your concentration upon them, and they will all explode at the same time.

Lighter nuts can only be thrown up to 10 feet away.  Larger and heavier nuts may be thrown up to 20 feet away.  Using a sling to throw the nuts will triple the distance you are able to throw them, but a ranged spell attack must succeed in order to place the nuts where you want them to fall.  Instead of throwing the nuts, they can be placed on the ground, perhaps to wait until someone walks near enough to them to be hurt by them.  Or they can be dropped from above upon unsuspecting targets.

If, AN ONLY IF, someone sees you drop or throw the nuts, they can make a dexterity saving throw against your spell DC to take half damage from the explosion.

AT HIGHER LEVELS:  For each level above 2nd level, you can cast this spell onto 2 additional nuts per level above 2nd level.