Homemade chili powder sprays can protect plants against insects and other pests that may be eating the garden. Chili powder spray won't kill all insects, but the spray will repel most insects and other pests that eat garden plants. It should not be sprayed directly on fruits, vegetables or herbs meant for the table as they could end up tasting like chili powder. Limit the spray to nonedible leaves.
Insects do not like plants with a strong odor or taste. The capsaicin that gives chili powder its hot flavor is distasteful to insects. Spraying plants or the soil around the plants with chili powder spray can keep insects from taking a taste. Because chili powder can be irritating to skin, wearing gloves while working with spray is recommended. Precautions need to be taken to keep the spray from getting into the eyes or on exposed skin as well, especially during windy weather.
For a basic chili pepper spray, add 1½ teaspoons of chili powder to 1 quart of water. Add two drops of liquid dish soap to help the spray adhere to surfaces. Like human skin, some plants can be irritated or burned by chili powder sprays, so always spray one or two leaves as a test. Leave the spray on the test leaves for several days to watch for a reaction. If the sprayed leaves are wilted, yellow or look burned, do not spray the plant with chili spray. The spray can be applied to the soil around sensitive plants and still be effective against many insects and garden pests.
To increase the potency of chili powder spray, garlic can be added. Chop an entire head of garlic and add to 1 quart of hot water, let steep for 24 hours. Strain the mixture through cheesecloth to remove the garlic pulp. Add 1 teaspoon of chili powder and two drops of liquid dish soap. Garlic can repel beneficial insects like ladybugs as well as pests, so this spray should not be used near areas where beneficial insects live.
Adding onion can also boost chili powder spray. Finely chop or puree a small onion and steep in water for an hour. Strain the liquid through cheesecloth to remove the onion pulp. Add 1 teaspoon of chili powder and half a teaspoon of liquid dish detergent. For persistent pests or a bad infestation, both garlic and onion can be added to the chili powder spray.
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