Most recently, […] The use of UV light to kill powdery mildew is a relatively new crop-protection strategy that also sterilizes your entire grow room. Save money on overpriced liquid formulations by mixing it yourself using potassium bicarbonate powder and an organic wetting agent.. These bulbs generate light at 254 nanometers (nm), a specific wavelength range of UVC energy known to kill … There are many brands of UV CleanLight on the market. Application: Make a 0.5–2.0% solution (5–20 grams per liter) of potassium bicarbonate to water. Potassium bicarbonate is a contact fungicide which kills the powdery mildew spores quickly. Potassium bicarbonate. Powdery mildew is a common summer problem on many types of vegetables and cut flowers. If vinegar does not seem to be cutting through your mold problem, try mixing it with borax, hydrogen peroxide, baking soda or salt. Overview: A lot of organic fungicide products for powdery mildew are simply potassium bicarbonate and a wetting agent in water. … But most powdery mildew can be avoided or cured with inexpensive, homemade remedies that have been proven to work as well as or better than commercial fungicides.. Vinegar is thought to kill 82% of species of mold. Warning. And that’s the premise. In addition, it’s approved for use in organic growing. If this is true, that still leaves you with the possibility of 18% of persistent species. Only mix the vinegar with one of these products at a time. Mouthwash – If it can kill the germs in your mouth, certainly the fungal spores of powdery mildew are no match. Does milk kill powdery mildew? If mildew and mold in tile grouting does not go away after you scrub with white vinegar and baking soda, clean the affected surfaces with hydrogen peroxide in a spray bottle. Can powdery mildew be cured?