Answer: Fungal diseases are generally caused by poor growing environments - too much shade, too much moisture in the soil, not enough good air circulation, water splashing on the leaves, the list goes on. Depending upon the type of fungal disease, there are various methods to control them. Baking soda and water works on some. Here's a list of other organic fungicide recipes:
Potassium bicarbonate Fungicide
Mix 4 teaspoons (about 1 rounded tablespoon) of potassium bicarbonate into one gallon of water. Spray lightly on foliage of plants afflicted with black spot, powdery mildew, brown patch and other fungal diseases. Potassium bicarbonate is a good substitute for baking soda. There are commercial EPA registered as well as generic products available.
Baking Soda Fungicide
Mix 4 teaspoons (about 1 rounded tablespoon) of baking soda and 1 tablespoon of horticultural oil into one gallon of water. Spray lightly on foliage of plants afflicted with black spot, powdery mildew, brown patch and other fungal diseases. Avoid over-using or pouring on the soil. Potassium bicarbonate is a good substitute for baking soda. Citrus oil and molasses can be used instead of horticultural oil.
Mix 3 tablespoons of natural apple cider vinegar in one gallon of water. Spray during the cool part of the day for black spot on roses and other fungal diseases. Adding molasses at 1 tablespoon per gallon will again help.
Manure compost tea is effective on many pests because of certain microorganisms that exist in it naturally. Here's how to make compost tea at home. Use any container but a plastic bucket is easy for the homeowner. Fill the 5-15 gallon bucket half full of compost and finish filling with water. Let the mix sit for 10-14 days and then dilute and spray on the foliage of any and all plants including fruit trees, perennials, annuals, vegetables and roses, and other plants, especially those that are regularly attacked by insects or fungal pests. It's very effective for example on black spot on roses and early blight on tomatoes. How to dilute the dark compost tea before using depends on the compost used. A rule of thumb is to dilute the leachate down to one part compost liquid to four to ten parts water. It should look like iced tea. Be sure to strain the solids out with old pantyhose, cheese cloth, or row cover material. Add two tablespoons of molasses to each gallon of spray for more power. Add citrus oil for even greater pest killing power.
Cornmeal Juice is a natural fungal control for use in any kind of sprayer. Make by soaking horticultural cornmeal in water at one cup per gallon of water. Put the cornmeal a nylon stocking bag to hold in the larger particles. The milky juice of the cornmeal will permeate the water and this mix should be sprayed without further diluting. Cornmeal Juice can be mixed with compost tea, Garrett Juice or any other natural foliar feeding spray.
Garlic Pepper Tea
To make garlic/pepper tea, liquefy 2 bulbs of garlic and 2 hot peppers in a blender 1/2 to 2/3 full of water. Strain the solids and add enough water to the garlic/pepper juice to make 1 gallon of concentrate. Use 1/4 cup of concentrate per gallon of spray. To make garlic tea, simply omit the pepper and add another bulb of garlic. Add two tablespoons of blackstrap molasses for more control.
Garrett Juice (ready to spray)
Mix the following ingredients in a gallon of water.
1 cup manure based compost tea
1 ounce molasses
1 ounce natural apple cider vinegar
1 ounce liquid seaweed
For disease and insect control add:
? cup garlic tea or
? cup garlic/pepper tea
or 1 ounce of orange oil
I can't vouch for these recipes because I've never tried them, but they are organic and friendly to the environment.
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