Sourced from the fruits and leaves of the neem tree, this stinky oil is an amazing pesticide that can work wonders in your garden.
What Is Neem Oil?
The neem tree (Azadirachta indica) is native to Southeast Asia. The oil is an important element in traditional Ayurvedic medicine, as well as soaps and cosmetics in its native region. Now that neem oil has gained popularity in the Western world, it’s becoming an increasingly common ingredient in everything from pet shampoo to foot powder.
Azadirachtin is the magic ingredient in neem oil. This compound not only kills bugs but also repels them, keeping your garden pest-free for weeks at a time per application.
The pure oil is dark gold, similar in appearance to olive oil. And it smells bad. We’re talking rotten garlic and boiled peanuts. The pungent odor isn’t so much of an issue when you’re using it outside, however. You shouldn’t eat neem oil or apply it directly to your skin or to your pets.
How Does It Work?
Neem oil is safer and less toxic than most other insecticides. It doesn’t harm plants, pollinators, or birds. Some studies have shown that it might negatively affect fish and other aquatic life, though.
It works when ingested by leaf-chewing insects. Plants absorb the active ingredients and it gets spread to any insects foolhardy enough to try chewing on your garden. The compounds in the oil cause insects to give up eating your plants and may also disrupt the hormones that allow the creepy crawlies to mature or mate.
It’s effective on many of the most common garden pests, including aphids, whiteflies, mites, and mealybugs. Even better, neem oil acts as a potent fungicide, taking care of a wide variety of mildew and mold issues.
How to Use Neem Oil
You can mix your own neem oil spray with up to a 50/50 solution of oil and water. Fill a spray bottle with the mixture and add a few drops of liquid Castile soap or dish detergent. You may need to shake the bottle periodically to prevent the water and oil from separating.
Only mix as much spray as you need that day; the compounds in neem oil start to break down in water after just a day or two.
Spray the plants you want to treat, including the underside of the leaves. Apply the oil in the early morning or late afternoon so that the leaves don’t get burned in the midday sun. It’s a good idea to spray the soil at the base of the plants as well.
Repeat treatment once a week for up to 6 weeks. That should take care of most common garden pests and fungi. If you have particularly stubborn nematodes, use a more aggressive soil drench to get rid of them.