Guide to Organic Pesticides

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You want a chemical-free garden, but how do you combat pests that like to devour our plants? Leave it to Mother Nature to protect our plants so you don’t have to use dangerous chemicals on your food supply. Learn more about how to naturally fight pests with this guide to organic pesticides.

Peppers & Onions

The pungent smell of onions, garlic, and peppers really bugs the bugs. Plant these veggies near your flowers or dice them and create a spray that infuses these scents. Use a garden sprayer to distribute the mixture evenly throughout your garden. You can spray a few times a week without harming the plants. Be careful about spraying this directly onto fruit or vegetables, though, since the mixture can give your tomatoes an odd flavor.

Companion Plants

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Plant borage and basil near your tomato plants to discourage tomato hornworms from devouring your crop. Basil repels the caterpillar-like creature and improves the taste of your tomatoes. Marigolds also give off a scent that discourages hornworms as well as mosquitoes.

Sage and green beans planted next to potatoes will keep flea beetles away. Catnip will deter the Colorado potato beetle (but also draw all the neighborhood cats to your yard).

Neem Oil

A powerful natural pesticide, neem oil is a popular organic pest control option. It’s a bitter tree leaf that will prohibit insect reproduction when turned into an oil. Add a teaspoon of neem oil and half a teaspoon of liquid soap to a quart of warm water. Stir the mixture and spray immediately onto your plants. This oil can also harm honey bees, so it’s best to spray early in the morning or late at night when bees aren’t active. You can also cover your plants for 24 hours after spraying to protect the bees.

Oil & Soap

Aphids and mites are top pests that plague gardeners every year. Creating an organic spray made of oil and soap will keep these pests from devouring a plant. Mix one cup of cooking oil with 1 tablespoon of natural liquid soap in a bottle. Shake the mixture and apply directly onto plants or any insects that you see in the garden. The oil will cover the spider mites, whiteflies, and lace bugs and kill them without hurting plant growth. Apply the spray about every 10 days for optimal use. You can also find pre-mixed commercial insecticidal soap at your local garden center. The soap is biodegradable so it won’t linger and harm the environment.

Mineral Oil

Using a mineral oil spray dehydrates insects as well as any eggs that they have laid. Since many pests lay their eggs on the underside of plant leaves, it’s best to check all sides of the plant. Spraying a mixture of 30 milliliters of mineral oil into 1 liter of water will create a natural and organic spray to use on plants.

Diatomaceous Earth

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You’ve probably seen this natural product in pet stores. Diatomaceous Earth kills fleas and ticks on cats and dogs as well as garden pests. The fine powder comes from fossilized plants found in the crust of the Earth. Sprinkle it around the base of your plants. The crushed fossils within the dust have minuscule sharp edges that most of us can’t see. These edges get underneath the wings of many pests but don’t harm the plants. It’s also great at killing bed bugs and ants, but perfectly safe for humans. In fact, Diatomaceous Earth is found in many natural kinds of toothpaste and facial scrubs.

Bt (Bacillus Thuringiensis)

Bt is a natural bacteria that lives in soil and creates proteins that are toxic to insects when eaten. The powder will kill the bugs, but will not harm other wildlife including pets or birds and bees.

Potassium Bicarbonate

Purchase this pesticide as a powder and combine it with oil to create a spray. Potassium Bicarbonate is helpful when fighting fungus on plants. Commercial options are available at local garden centers as well. The spray acts immediately and lasts for a few weeks.

Fight Pests with More Pests

organic pesticides
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Nematodes are tiny worms that kill cutworms, Japanese beetle larvae and root maggots. You can buy them at any home improvement store and add them directly to the soil. In addition to killing soil-dwelling pests like grubs, they can enrich the nutrients in the ground and help your plants grow stronger.

Fighting pests is something that every gardener needs to address during the growing season. Applying these organic pesticides can help reduce chemical interference in the garden and protect the earth for years to come. Consider this guide to organic pesticides the next time the bugs are bugging you.


Jack Malone is a farmer and freelance writer who prides himself being eco-friendly. He enjoys finding new ways to practice green-farming with no chemicals.