Manage Diseases Naturally

Damp Northwest weather is perfect for growing fungus and bacteria, but difficult for some plants (especially non-native varieties). Luckily, there are easy ways to prevent diseases like black spot and powdery mildew without hazardous chemicals.

Build healthy soil. It grows healthy plants. Healthy plants are less likely to be harmed by diseases. Compost and organic fertilizer will enrich your soil with nutrients, help hold water, loosen clay and feed beneficial soil life. Consider testing your soil to determine which plants may thrive, or help detrmine which soil amendments could boost your plants' health.

Choose disease-resistant plants. Opt for native plants, or non-natives adapted to your seasonal conditions (Western Washington = wet-winter with mild summer climate; Eastern Washington = freezing winter and very dry summer). Whenever possible, choose the right plant for the right place.

Avoid the few natives prone to problems in garden settings. Try a dogwood resistant to anthracnose or a maple resistant to verticillium in the place of susceptible native varieties.

Give roses lots of sun and air. Keep the leaves dry to discourage most diseases. Plant them where they’ll get six hours of sun a day. Prune to improve air circulation and clean up diseased leaves.

Water early in the day. When you water your plants, do it early in the day so plants dry completely before sundown.

Treat diseases and insects separately. 2-in-1 products treat disease and insects. Using these products may kill beneficial insects that are helping keep nuisance insects in balance.

Use pesticides as a last resort. Many fungicides contain hazardous ingredients, but there are products available with safer ingredients like sulfur, jojoba oil, or potassium bicarbonate.

If you decide to use a pesticide, pick a safer product for people, pollinators and the environment by using the product rankings in the Grow Smart, Grow Safe product tables.