How to Get Rid of White Powder Mold on Plants With a Vinegar Mix

Joan Norton

Dusty white or grey spots on the leaves, stems, flowers or fruit of plants and shrubs is caused by fungus. If left untreated it easily spreads to become a thin, white powdery coating on the entire plant. Young foliage and shoots are the most susceptible to excessive powdery fungal growth.

Vinegar is an effective fungicide spray for powdery mold.

Early signs of the disease are leaf curling and twisting. Powder mold does not kill the plant but will hasten its defoliation, prevent normal flowering and cause early dormancy. It is common on all types of ornamental plants and flowers. Lack of adequate air circulation contributes to the development of powdery mildew. Vinegar is an effective home remedy for the problem.


Space plants for good air circulation. Overcrowded conditions set the stage for fungal problems. Use mature compost as part of the potting soil mix and as outdoor fertilizer. Compost helps soil balance fungal and bacterial populations and prevents disease.


Roses, phlox and zinnia are highly susceptible to powdery mold and should be planted in areas that receive full sun. Do not handle or work with plants when the foliage is wet. This may spread fungi spores. Avoid overhead water sprinkling that leaves foliage damp. Water in the morning only.

  1. Pour 2 tbsp. undiluted vinegar into the spray bottle container. Hand-held plastic sprayers are easy to use for household plants and hose-end sprayers work well for larger outdoor areas. Use one part vinegar to 20 parts water in any size container.

  2. Shake or stir the water-vinegar mixture and begin to spray. Cover all parts of the plant, especially the underside of leaves. Vinegar is a contact fungicide that is effective only when fungi spores are sprayed directly.

  3. Repeat the application weekly until the powdery mold is gone. Continue to monitor plants for small round dots of white or gray fuzzy growth, which indicates a re-emergence of the fungus.