Ever eagerly buy a bag of potting soil to transplant your well looked after sprout into a bigger pot, or plant some recently acquired greenery—just to have the soil spawn teeny black flies? These pests will appear in any soil—expensive or cheap, and it’s happened to me one too many times. But thanks to my boyfriend’s step mom, and confirmation from an Arctic dweller online, I have discovered a surefire technique that results in permanent gnat extermination.
Dallas-Lee of an unnamed Arctic location confirmed the only thing consistently killing the gnats and their eggs dead is baking the dirt.
I’ve found placing the dirt in a deep baking dish and heating it through at 300ºF for ~20 minutes does the trick—only bake the amount of soil you need to use and don’t worry about preheating. Or better yet, find a potting soil that has been pre-through heated.
If remaining soil begins hatching its own flies, return it. Most soils come with a 1-year warranty. Simply place the soil inside a plastic bag and tightly tie it shut to contain the flies while returning.
Happy house planting