Knock out nasty plant pests with the natural, safe and environmentally friendly pesticide neem oil
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Discovering icky insects binging on your prized plant’s leaves can induce panic in the heart of any gardener. But getting rid of aphids or other plant pests is all about being calm and nipping the problem in the bud—before you end up with a dead plant. Frequently, hosing down your indoor plants with water can be enough to eradicate the hangers-on. But, if an infestation is out of control, you might be considering neem oil for plants to help you get rid of spider mites or other bothersome bugs.
You can easily pick up a chemical pesticide from your local garden center. But if you’d rather avoid harmful chemicals that can be risky for people, pets and the environment, there are low-impact alternatives like neem oil to help you get rid of mealybugs or other creepy crawlies. Master gardener Beth Buckley explains that, as far as pesticides go, neem oil is one of the better ones. “It’s naturally occurring, low in toxicity and has a long history of use,” she says. Check out these expert-approved tips for how and when to use neem oil to banish the bugs.
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What is neem oil?
Neem oil is a naturally occurring pesticide coming from the seeds of the native South Asian neem tree (Azadirachta indica). It’s also used in traditional Ayurvedic medicine, and you can find it in things like heating fuels, soaps, cosmetics and toothpaste. The main active ingredient within the oil enabling it to work as a pesticide is azadirachtin.
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How does neem oil work on plants?
You can use neem oil to control infestations of common houseplant pests. These include aphids, spider mites, beetles, mealybugs, thrips, whiteflies and leaf miners. It’s effective during their immature phases, but it won’t kill adult bugs. Plus, “insects that have hard bodies or protective shells (like scale) are completely unbothered by neem oil,” Buckley says.
“Azadirachtin works by inhibiting pest metabolism and hormones, and the oil can literally smother soft-bodied insects,” she explains. The oil blocks the breathing pores of the pests in the same way that an insecticidal soap does. The azadirachtin interrupts feeding, growth and reproduction in the insects when they eat it and acts as a repellent.
However, “azadirachtin must be ingested by an insect to be effective,” Buckley says. “If the pest does not feed on leaf tissues—like root mealies, for example—it won’t ingest any neem.” And immediate results are rare. Repeated applications are typically necessary to wipe out a bug invasion.
Studies also show neem oil effectively limits the spread of the common fungal diseases rust and powdery mildew.
What plants benefit from neem oil?
You can use neem oil on a wide variety of plants, vegetables and fruits as part of your pest-management strategy. But it always pays to test on a small area of an individual leaf before smothering all a plant’s foliage in this stuff. You should avoid using neem oil on recent transplants or plants showing signs of stress.
If in doubt, Buckley recommends exhausting other natural pest-management options before turning to neem oil for plants. “In my opinion, the safest, most natural and best way to treat pests on plant leaves is with a strong blast from the hose,” she says. “Using beneficial predatory insects is another great [option]. Lacewings, soil mites, nematodes and many others are great at keeping pests in check.”
What plants should you not use neem oil on?
Some trees, including black walnuts, Douglas firs, junipers, maples, redbuds and spruces, are sensitive to horticultural oils such as neem. And there are precautions for use on sensitive plants, which include impatiens, fuchsia, hibiscus and some rose and carnation varieties. Neem oil is more likely to burn and damage their foliage.
Plus, when plants have textured foliage, like calatheas, results might not be as effective because it’s tricky to get complete oil coverage. This makes it easier for bugs to escape a smothering or munch on oil-free sections of foliage.
Depending on how sensitive your sense of smell is, you might want to stick with using neem oil on outdoor specimens rather than your indoor plants. “Neem oil stinks,” Buckley says. “Some folks don’t mind it, but in my opinion, the strong sulfur/rotten onion smell is very unpleasant, especially for indoor use.”
How do you use neem oil for plants?
Carefully follow the manufacturer’s instructions when applying a commercial neem oil spray for plants. Going the DIY route is also possible by making your own non-toxic pesticide.
Make your own neem oil spray
Mixing your own neem oil spray for plants is straightforward. Plus, it offers more control over strength and additional ingredients. Follow the steps below to blend and apply your bug-busting mixture.
Step 1: Create a soapy water mixture
Fill a one-liter spray bottle almost to the top with tap water. Mix in 1/4 to 1/2 teaspoon of mild dish soap. Adding the emulsifying soap is an important step to help improve the neem oil’s solubility in water. Shake the bottle well.
Step 2: Add neem oil to the mix
A little goes a long way with concentrated neem oil. Add 1 to 2 teaspoons to the soap-and-water mix and shake thoroughly to blend until it has a cloudy appearance. Using warm (not hot) water helps the neem oil blend better.
Step 3: Test the spray
Don’t douse your plant straight away with the spray. Check its sensitivity and the strength of the solution by testing on a small section of one leaf. Then wait 24 hours. If the plant shows signs of damage or discoloration, try diluting the solution further or opt for an alternative pest-management strategy.
And even if your plant hasn’t objected to neem oil application before, it’s always advisable to retest. Some plants can be more sensitive at certain times of the year.
Step 4: Spray the plant’s surface with care
Don protective gloves before spraying the surface and underside of the plant’s leaves. A light, even coating rather than a smothering is best to ensure your plant can fully absorb the light it needs and to minimize the chance of soaking leaves starting to rot or develop fungal problems. Consider also gently rubbing the spray into the leaves to promote the best coverage. The coating should take around 30 minutes to an hour to dry.
Step 5: Make a fresh mixture when reapplying
You will probably have to reapply the spray to eradicate all the bugs on your plant. Dousing daily for a week is sometimes the best strategy when there are hordes of creepy crawlies. When your plant doesn’t have too many tiny visitors, a treatment once every week should be ample.
The active ingredients in DIY neem oil sprays for plants lose their effectiveness fairly quickly once blended with water. Don’t mix up a huge batch all at once. It’s best to just keep enough for using over the next day or two.
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Bonide Captain Jack's Neem Oil
Frequently asked questions
When should you use neem oil for plants?
Spraying plants with neem oil at dusk or dawn is best. That way you’re less likely to risk harming beneficial pollinators like bees. It also reduces the chance of your plant developing brown tips on the leaves because of scorching when the neem oil dries under direct sun.
You can apply neem oil in any season, but avoid using it during extreme temperatures—above 100 degrees or below freezing. Wait for a dry day too, as the oil won’t evaporate well when wet.
How much neem oil do you use for plants?
Neem oil is a concentrated product. Using too much can result in leaf scorch or other damage to your plant. When making your own spray for plants, a ratio of around 1:100 (one part neem to every 100 parts water) usually works.
Can I put neem oil directly on soil?
Applying a neem oil mix as a soil drench when you’re watering your plants is another way to ward off pests. The roots absorb the active ingredients, and the insects still get them into their system when eating the leaves.
Is neem oil safe for pets?
“Azadirachtin can be slightly irritating to your skin or eyes if it comes in contact with them, but in general, it’s one of the safest pesticides to use indoors or around pets,” Buckley says.
When applying the spray, it’s best to have your pets in another room. But if your pets nibble on foliage sprayed with neem oil, unless it’s a plant that’s poisonous for dogs or you have a houseplant that’s toxic for cats, it isn’t a major cause for concern.
Sources:
- Beth Buckley, master gardener
- National Library of Medicine: “Neem: A Tree for Solving Global Problems”
- Colorado State University: “Insect Control: Horticultural Oils”
- University of Nevado, Reno: “Horticultural Oils – What a Gardener Needs to Know”
FAQs
How to Use Neem Oil on Plants to Protect Against Pests? ›
During the growing season, use neem oil as a repellant or to control infestations. Apply as a foliar spray or soil drench. Dilute neem oil concentrate with water and add a bit of liquid soap, which will help to mix the water and oil. Use a pump sprayer to cover a large area and reapply as needed.
How do you protect plants from pests with neem oil? ›- Gather your materials. Buy cold-pressed neem oil, liquid soap, a spray bottle, and a gallon of water.
- Combine water with a small amount of soap. ...
- Add a small amount of neem oil. ...
- Apply the mixture to your plants. ...
- Reapply the mixture as needed.
You can use Neem Oil on most plants, but it won't be effective on plants that don't have smooth surfaces. If your plants have fur, needles, and any other way to allow pests to crawl deeper in the leaves to escape the Neem Oil, it won't be effective.
How often to spray infested plants with neem oil? ›How often should you apply neem oil for plants? You should apply it around one or two times a week to get the acute infestation under control. If you just want to prevent your plants from any pests, you can use the neem oil every 7- to 14 days.
What happens if you spray too much neem oil on plants? ›Using too much neem oil can cause leaves to burn if they are exposed to direct sunlight for a prolonged period. You should also avoid using neem oil on young or small plants, as it may be too strong for their roots and buds.
Do you spray neem oil on soil or leaves? ›Foliar spray: Use neem oil directly on leaves anytime during the planting season to control pests and diseases. Soil drench: A soil drench is when neem oil is diluted with water and poured into the ground or potting soil.
What plants should not be sprayed with neem oil? ›Neem oil should not be sprayed on herbs such as basil, caraway, cilantro, dill, marjoram, oregano, parsley, or thyme. Care should be taken when spraying neem oil on plants that have delicate or wispy leaves–such as arugula, lettuce, peas, and spinach–since this can result in foliage burns.
Is there anything you shouldn't spray neem oil on? ›Neem oil shouldn't be used on herbs such as basil, caraway, cilantro, dill, marjoram, oregano, parsley, or thyme. Spraying neem oil on plants with delicate or wispy leaves, such as arugula, lettuce, peas, and spinach, should be done with caution because it can cause foliage burns.
Do I need to wash neem oil off plants? ›Neem oil is an excellent natural solution for serious pest infestations. Simply spray the entire plant—leaves, stems, and soil— with neem oil once a week until there are no more signs of pests on the plant. There is no need to wipe it off.
Does neem oil need to be diluted for plants? ›Cold pressed neem oil is highly concentrated and needs to be diluted for use. You will need either a one-quart spray bottle for small applications, or a one-gallon pump sprayer for larger applications. Always follow specific mixing instructions listed on the product label.
Should I spray neem oil at night or morning? ›
Aim to apply neem oil in the early morning or late evening. Beneficial insects are usually less active at these times, making them less likely to come in contact with the pesticide.
Can pests become resistant to neem oil? ›21. Insects don't become resistant to neem oil. Insects do not become immune to neem oil pesticides, as they can with other types of pesticides. This means that neem oil remains effective, even after repeated applications.
How long does neem oil last on plants? ›Azadirachtin, a major component of neem oil, is rapidly broken down. Microbes and light break down the pesticide in soil, water and on plants. The half-life of azadirachtin in soil ranges from 3 - 44 days. In water, the half-life ranges from 48 minutes to 4 days.
What happens if you don't dilute neem oil? ›Some people may experience skin irritation if they come into direct contact with neem oil that hasn't been diluted.
Is neem oil toxic to dogs? ›Neem oil is a natural compound found in the seeds of the neem tree. It has many uses, most notably as a pesticide. It repels and kills bugs. The difference between the oil and the pesticides well-known for their chemical composition, is that neem is completely natural and generally safe for dogs.
What percentage of neem oil should I spray? ›Step by Step Process of Making Your Neem Oil Spray
To make 1 liter of a mild 0.5% basic neem oil spray, you will need: 5 ml (1 teaspoon) of neem oil. 1 liter of warm water. 1-2 ml (⅓ tsp) of mild liquid soap or another mild detergent.
A systemic treatment is one that gets applied when watering. The neem oil solution is then absorbed by the plant through the root system and taken up through the leaves. This means when any chewing or sucking insects try to feed on the leaves of your plant, they will ingest the insecticide and die.
Where do you spray neem oil? ›Spray all plant surfaces (including tops and undersides of leaves) until completely wet and dripping. Use protective gloves to avoid any oily drips.
Do you wash off neem oil after spraying? ›Plants sprayed with neem oil don't need to be rinsed off, although fruit harvested within a week of spraying should be washed well with soapy water. Neem oil will dry in a few hours, but its insecticidal elements will break down completely within 2-5 days after the initial application.
What bugs hate neem oil? ›Neem oil repels a host of insects, including aphids, mealybugs, spider mites, thrips, squash bugs, and whiteflies. Unchecked, these tiny pests can do a lot of damage. One of the main components of neem oil, azadirachtin, adversely affects insect hormones that enable growth and reproduction.
Can you apply neem oil in the sun? ›
Never apply neem oil in the middle of the day or during sunny conditions. Applying foliar sprays in direct sunlight can cause the wet leaves to sunburn. Fully drench the target plant until the leaves are dripping. Give your sprayer a shake here and there to keep things mixed.
What happens if you leave neem oil on overnight? ›Can you leave neem oil on overnight? A. Neem oil is potent, therefore leaving it overnight on your skin can cause irritation. You can apply it for one to two hours and wash it off with lukewarm water or use diluted oil.
Can I use neem oil without carrier oil? ›Because of the potency of neem oil, it's a good idea to mix it with equal parts of a carrier oil — like jojoba, grapeseed, or coconut oil — when using it for larger areas of the face or body, or on sensitive skin.
How long does neem oil last once applied? ›How long will your neem oil spray last? According to manufacturer recommendations, diluted neem oil will retain its full potency for up to 24 hours, although most neem oil sprays will retain some degree of efficacy if applied within 3-4 days after initial dilution.
Can I spray neem oil directly on soil? ›Spraying Neem Oil directly on plants is not recommended. Always dilute the oil before spraying. To ensure a well-mixed solution, use lukewarm water.
What is the ratio of water to neem oil? ›Neem oil is most commonly sold as a concentrated solution which should be mixed at the rate of two tablespoons per one gallon of water for foliar (leaf) application.
Does neem oil attract any bugs? ›The smell of the oil is enough to repel most insects so they don't even come near your garden or plants. Neem oil also contains azadirachtin, which is the main active ingredient. Azadirachtin reduces the feeding of sucking and chewing insects.
Do mosquitoes hate neem oil? ›Neem Oil. Neem oil is one of the safest natural methods to keep the mosquitoes away from your body as well as your home. The effectiveness of neem oil will last approximately 3 hours and repel 70% of the mosquitoes. However, neem oil should not be used on the skin as it can lead to skin irritation.
What are the side effects of neem oil? ›Special Precautions & Warnings
These serious side effects include vomiting, diarrhea, drowsiness, blood disorders, seizures, loss of consciousness, coma, brain disorders, and death. Pregnancy and breast-feeding: Neem oil and neem bark are LIKELY UNSAFE when taken by mouth during pregnancy.
mellifera adult workers. However, andiroba oil, garlic extract, and neem oil demonstrated an acute toxicity to bee larvae.
What plants are sensitive to neem oil? ›
Neem oil shouldn't be applied to plants like caraway, basil, cilantro, marjoram, dill, parsley, oregano, as well as thyme. Be cautious in spraying the neem oil onto plants with delicate or wispy leaves, such as peas, arugula, lettuce, and spinach, as this could cause burns to the foliage.
Is breathing in neem oil toxic? ›CAUTION Harmful if inhaled. Avoid breathing spray mist. Causes moderate eye irritation. Harmful if absorbed through skin.
Does neem oil repel ticks? ›Neem seed oil has been shown to kill tick larvae in cattle. Strong anecdotal evidence indicates that it repels ticks and, when applied to ticks, can also help dislodge them from skin.
Is neem oil toxic to humans? ›Assessing Risks to Human Health
No risk to human health is expected from the use of Cold Pressed Neem Oil because of its low toxicity via all route of exposure. Cold Pressed Neem Oil has been used for hundreds of years to control plant insects and diseases.
Mixing Instructions: Mix Garden Safe Brand Neem Oil Extract Concentrate at the rate of 2 Tbsp (1 fl oz) per gallon of water. Thoroughly mix solution and spray all plant surfaces (including undersides of leaves) until completely wet. Frequently mix solution as you spray.
Can you put neem oil directly in soil? ›Another way to apply neem oil is in a soil drench, which involves pouring the diluted solution directly on the soil. This is a good method for treating fungus gnat larvae, nematodes, and other soil-borne pests.
Can I spray neem oil on soil of houseplants? ›Neem oil also prevents fungal problems in the soil when applied as a soil drench! Neem oil is the perfect pesticide choice for those who prefer the organic route and keep harmful chemicals away! Houseplants such as hoyas, and philodendrons, and pothos that have many leaves will benefit from preventive neem oil mists.
Why not to use neem oil? ›Neem oil can be slightly irritating to the eyes and skin. Azadirachtin, a component of neem oil, can be very irritating to the skin and stomach. The remaining portion of neem oil is made of fatty acids, essential oils and other substances that are commonly eaten in a normal diet.
How long to let neem oil sit on plants? ›Spray the leaves, stems, and soil with your ready-to-use neem oil spray. (It should have that clarified hydrophobic neem oil to trap bugs instantly.) Let sit for two to three days. Keep it away from your other plants and out of the sun.
Why did Canada ban neem oil? ›In 2012 there was a ban placed on the import and export of Neem oil and related products due to the fact that Neem oil was never registered as a pesticide in Canada (Celli, 2016).
Do I need to rinse neem oil off plants? ›
Simply spray the entire plant—leaves, stems, and soil— with neem oil once a week until there are no more signs of pests on the plant. There is no need to wipe it off. Be careful— some neem oil comes in concentrate and will require diluting.
Can I put neem oil in water for plants? ›Watering your plant with a diluted solution of neem oil will help rid the soil of the larvae without harming your plant.
Do plants soak up neem oil? ›It's also effective at getting rid of fungi and mildews like root rot, sooty mold, and powdery mildew, likely because of its antibacterial properties. Interesting Fact: The coolest thing about neem oil is that many plants absorb it through their roots when it's applied to the soil.