Homemade Fungicide for Tomatoes

Baking Soda Fungicide

Baking soda is a white soluble compound that is often used as a fungicide on plants. Mix 4 tsp. baking soda and 1 tsp. horticultural oil, citrus oil or molasses into a gallon of water. Shake it up well until the baking soda has dissolved. Put some of this mixture into a spray bottle and spray it onto any parts of the tomato plant that display symptoms of fungal diseases such as mildew, black spot or brown patch. If you don't have baking soda, potassium carbonate is a good substitute.

Another common kitchen ingredient that can serve as a tomato fungicide is cornmeal. According to organic gardener Howard Garrett, cornmeal has natural anti-fungal properties and can be used in any type of sprayer when mixed with water. To make a cornmeal juice spray, soak 1 cup of cornmeal in 5 cups of water for an hour, or until the water looks opaque and milky. Strain the solid cornmeal out then spray the resulting milky liquid onto your tomato plants.

Vinegar, too, is found in most kitchens and has effective anti-fungal properties for plants. To make a vinegar fungicide for tomatoes, dilute 3 or 4 tbsp. of vinegar in a gallon of water and spray the mixture onto your tomato plants. Apple cider vinegar is the most natural type of vinegar, but Howard Garrett claims that white vinegar is the most effective when it comes to doing away with fungus on plants.

Several essential oils also have natural anti-fungal properties, among them citrus oil, peppermint oil, oregano oil, clove oil, grape root oil and orange oil. You can mix any of these into another type of homemade fungicide, or use them diluted in water.

Compost tea is a concoction made of compost diluted in water, and it gets its name from the iced-tea color of the diluted liquid. To make compost tea, fill a bucket with equal parts compost and water. Let this mixture percolate for 10 to 14 days then strain out the solids and dilute it in water until it becomes thin enough to spray. Apply the mixture to the foliage of your tomato plants, especially where fungus is visible.