Placing powdered milk on a stump can actually help to expedite its breakdown and deterioration. The milk acts as a super food source for bacteria and fungi that often inhabit rotting wood. The milk provides additional nutrients that encourage the growth of bacteria and fungi, which speeds up the rotting process of the stump.
Remove as much of the stump from above ground level as possible. Use a saw, axe or stump grinder to take the stump down to ground level.
Score the top of the stump with an axe to create areas for holding the powdered milk. Vary the size and direction of the cuts.
Wet the top of the stump with a mixture of household plant food and water. Mix 1 tbsp of indoor plant food per gallon of water. Mix 3 to 4 gallons of water as a rule of thumb. The plant food will provide extra nitrogen for the rotting process.
Sprinkle the powdered milk over the top of the wet tree stump. Work the powdered milk into the cuts and scoring on top of the stump.
Cover the stump with dirt. Shovel 2 to 3 inches of topsoil or potting soil onto the stump to completely cover it. Apply water to the stump periodically to encourage bacteria and fungi and add more dirt as necessary to keep it covered.