DIY Fungicides: Safe, Homemade Recipes for Garden Fungal Diseases

Fungal diseases (powdery mildew, black spot, blight) can ruin a harvest — but harsh chemicals aren't your only option. Many effective fungicides can be made from kitchen and garden ingredients. They're cheaper, safer, and often work just as well for prevention and early treatment.

First: Reduce the Need

• Choose disease-resistant varieties.
• Space plants for airflow.
• Water at soil level, not foliage.
• Remove infected leaves promptly.
• Rotate crops annually.

Popular Homemade Fungicide Recipes

• Baking soda spray: 1 tbsp baking soda (or potassium bicarbonate) + 1 tsp mild liquid soap (no degreaser/bleach) + 1 gallon water. Spray weekly.
• Oil-based: 1 cup cooking oil + 1 tbsp soap + 1 gallon water. Helps mixture cling to leaves.
• Pyrethrin (from painted daisies): Dry flower heads, grind, soak in 1/8 cup alcohol overnight. Strain, dilute to 4 gallons water. Botanical, broad-spectrum.
• Bordeaux mix (dormant season only): 4-4-50 ratio — 4 parts copper sulfate + 4 parts hydrated lime + 50 gallons water. For small batches: 6.5–8 tsp copper sulfate + 3 tbsp lime per pint water. Controls fungal/bacterial diseases on fruit trees.

Critical Safety Rules

• Test on a few leaves first — wait 48 hours for damage.
• Never spray in hot sun or above 85°F — causes leaf burn.
• Avoid bleach-based soaps.
• Wear gloves/eye protection.
• Label and store safely away from kids/pets.

"Organic" doesn't mean harmless. Use homemade sprays responsibly.