20 Brilliant Ways to Repurpose Old, Spoiled Milk

5. Give your plants a calcium boost

While you’re pouring rotten milk down mole and vole tunnels, you might as well pour some on your plants. The bacteria-laden stuff is too harsh for our tummies, but your plants and soil will certainly benefit from the calcium and beneficial bacteria. Make sure to dilute the stuff in a 1:1 mixture with water. Spray the solution onto the leaves and soil for quicker absorption.