Homemade Rose Fungicide: Baking Soda Spray for Rust and Mildew

A gardener asked about dish soap spray for rust prevention (father-in-law's method), wanting the recipe since chemicals failed.

Why Modern Dish Soap Fails

Old soaps = fatty acids (organic). Modern soaps = synthetic detergents. Can damage roses at high concentrations.

Proven Organic Formula

Mildew & Black Spot Spray:

• 8 cups water
• 1 tablespoon baking soda
• 1 tablespoon white vinegar
• 1 tablespoon canola oil
• Hose off leaves morning → spray daily (mildew) or weekly (black spot)

Organic Bug & Fungus Spray:

• 1 quart water
• 1 tablespoon baking soda
• 1 tablespoon canola oil
• Few drops dish soap (sticker only)
• Targets leaf-eating insects

Rust-Specific (Simpler):

• 1 quart water
• 1 tablespoon baking soda
• 3 drops dish soap (sticker)
• Spray every 8-10 days

Application Keys

• Morning only (avoid leaf burn)
• Full coverage (undersides too)
• Reapply after rain
• Test on few leaves first

These recipes work preventively. Severe infections need commercial fungicides. But for maintenance—cheap, safe, effective!