A Complete Guide to Neem Oil for Indoor Plants
Experienced houseplant enthusiasts often agree that neem oil is their first choice for indoor pest management. This isn’t surprising since consumers everywhere have been moving toward natural products.
However, what exactly is neem oil, and how does it eliminate pests? How long should you leave neem oil on your plants, and which pests does neem oil treat? Here, we’ll discuss these important concepts around neem oil for indoor plants.
What is Neem Oil?
Neem Oil is a naturally occurring pesticide extracted from the neem tree (Azadirachta indica), which grows in India, Sri Lanka, and Burma. Neem oil is commonly used in both indoor and outdoor gardens. Since it is a natural pesticide, neem oil is typically gentler on houseplants than chemical products.
When neem oil is harvested, it is extracted from the seeds produced by the neem tree through the process of cold pressing. This process preserves the pest-fighting active ingredient, azadirachtin. To ensure you are getting an effective product, look for labels that state “cold-pressed neem oil.”
Neem oil for houseplants is packaged the same way as neem oil you might use in your outdoor garden. It is often sold concentrated and requires dilution before applying it to your plants. The best method is to purchase a separate spray bottle for your diluted neem oil and label it for continued use.
Also, neem oil products may have different concentration percentages on the labels. Because not all products require the same dilution measurements, read the instructions carefully.
Another tip is that neem oil is sometimes overpriced in retail garden centers. You’ll often find a less expensive cold-pressed neem oil on Amazon.
Additionally, neem oil can be purchased in a pre-diluted, ready-to-use spray. The active ingredient is usually listed as clarified hydrophobic neem oil in ready-to-use neem oil sprays.
While neem oil is a naturally occurring pesticide, manufacturers often combine it with chemical pesticides in many commercial products. When purchasing neem oil for houseplants, you may see labels with the word “Neem” listed in large letters. However, be sure to read the active ingredients because these products still might contain other ingredients you may not want on your indoor plants.
How Neem Oil Works for Houseplants
Neem Oil for Pest Management on Houseplants
Neem oil treats insect pests by deterring them and disrupting their life cycles.
1) For other pests, such as spider mites, neem also kills on contact. Mites are arachnids rather than insects, and neem oil suffocates them. Because neem can kill mites on contact, it is labeled as a miticide.
2) However, most insect pests are not killed immediately and eventually die off from the secondary effects of neem oil.
For example, insect larvae will ingest the active ingredient azadirachtin when neem oil is applied to your plant’s foliage. Once in their system, this ingredient interferes with larval development. It prevents larvae from growing further, and they die off.
3) While neem oil usually doesn’t kill adult insect pests on contact, the application of neem makes your plant’s foliage unpalatable for them. As a result, adult pests will stop feeding and eventually die.
For this reason, you should isolate infested plants or treat your entire collection. This will prevent pests, such as adult thrips, from moving over to feed on one of your untreated plants.
Because the effects of neem on pests vary depending on life stages, reapplication is required to eliminate indoor pests of all kinds.
Which Pests Does Neem Oil Treat?
Common houseplant pests neem oil treats:
- Spider mites
- Fungus gnats
Neem oil treats over 200 pests, including outdoor pests such as Japanese beetles and leafhoppers. Furthermore, neem oil prevents the spread of most fungal infections.
- How to Get Rid of Spider Mites on Your Calathea
- How to Identify, Treat & Prevent Thrips on Your Monstera
Neem Oil for Fungal Infections on Indoor Plants
Additionally, neem oil can treat fungal diseases such as powdery mildew, rust, black spot, anthracnose, leaf spot, and mold scab. When applied to the leaves, the oil acts as a barrier to prevent fungal spores from penetrating leaf tissues.
Although neem oil does not cure sections of plants already infected with fungal disease, it prevents the spread of the infection to the rest of the plant.
Therefore, if the fungal infection has not reached more than ⅓ of your plant, you can still save your indoor plant with neem oil. Remove the diseased portion and treat the remaining parts of your houseplant with neem oil.
Once a fungal infection has progressed to more than ⅓ of your plant, you can still try this treatment method. However, the indoor plant will have a lower chance of survival due to the combined stress.
Is Neem Oil Safe for People and Pets?
As with any pesticide used inside the home, safety is a valid concern. Fortunately, neem oil is safer for your household than many other chemical pesticides.
However, neem oil should be used carefully since there have been limited studies on how it may affect everyone.
Neem Oil can be Harmful to Anyone if Ingested
Whether neem oil is toxic to humans and other mammals is often debated. We can conclude that neem oil has some toxicity when ingested due to rare reports of neem poisoning in small children and older adults. Although neem oil is not considered highly toxic, it can cause harm when misused.
In cases where neem oil has caused health complications in people, it was ingested in high concentrations. Additionally, a 90-day subchronic toxicity study on rats found that neem oil caused damage to kidneys, liver, and reproductive organs when ingested in large amounts over time. Scientists have been unable to pinpoint a threshold at which the amounts of neem oil ingestion become toxic to people. Therefore, consuming neem oil should be avoided entirely unless medically directed. If accidentally ingested, seek medical advice.
Avoid Neem Oil During Pregnancy and Protect Your Eyes
By following standard precautions, this plant extract is safe to use around most people. Due to limited data on neem oil exposure during pregnancy, those who are pregnant or may become pregnant should avoid handling this plant extract. Furthermore, neem oil is a mild eye irritant and should be thoroughly rinsed if accidentally sprayed in the eyes. While it is not usually a skin irritant, some people may have skin sensitivities to neem oil.
Diluted Neem Oil is Safe to Use Near Dogs and Cats
When neem oil for houseplants is used correctly, it doesn’t pose a risk to dogs and cats.
The ASPCA does not classify the neem tree as a toxic plant for dogs and cats. However, veterinarians are cognizant in pointing out that concentrated neem oil could be harmful to pets. This is because oils extracted from plants are more potent than they occur in nature.
Like other plant oils, even natural ingredients are best to avoid around your pets in high concentrations. Due to its high potency, veterinarians have stated that concentrated neem oil can be hazardous to pets if ingested or spilled on their skin.
In the diluted concentrations we use on our houseplants, neem oil is not toxic to dogs or cats. This makes it a safe option in most households with pets.
Avoid Spraying Neem Oil Near Birds and Fish
While diluted neem oil has been listed as relatively safe around birds and mammals alike, there is limited data available on birds, to be certain.
Other than the natural oils their bodies produce, birds can’t handle other kinds of oil on their feathers. Therefore, pet birds should be far away from neem oil spray droplets.
Also, since birds have highly sensitive respiratory systems, it is safest for them not to inhale neem oil fumes. Once dry, neem oil shouldn’t be irritating for them. Like other pets, prevent ingestion as well.
Lastly, neem oil has mild toxicity for fish and other aquatic life. Because fish are sensitive to tree oils, you should avoid spraying neem oil (even diluted) near your fish tanks.
How to Use Neem Oil for Indoor Plants
Foliar Spray Method
1. For heavy insect infestations, wash your plant with insecticidal soap in a bathtub or shower before neem oil application. Since neem oil does not kill most adult insects on contact, insecticidal soap will help jumpstart pest removal.
For fungal infections, remove the diseased portion of your plant and continue the steps below.
2. Prepare your neem solution. These steps will vary depending on the type of product you have purchased.
- Mix concentrated cold-pressed neem oil with warm water using the measurements indicated on the label.
- For pre-mixed or ready-to-use neem oil for houseplants, shake well before application. The neem oil often settles on the top between uses.
3. Spray one leaf of your plant with your diluted neem oil first to test the plant’s response. Some plants are sensitive to neem oil. Keep your plant out of direct sunlight, and allow 24 hours to ensure that the leaf does not have an adverse reaction to neem before applying more.
4. Place your plant in a bathtub or shower to prevent messes while spraying it down. Also, keep your pets away.
5. Thoroughly spray the diluted neem oil on your entire plant. Include the front and backsides of leaves, stems, crevices, and the top layer of soil.
6. Allow your plant to air-dry, and keep it out of direct sunlight while oil is on its leaves. Since neem oil takes time to work for most pests, it may take at least two days to see a reduction in pest numbers.
7. Quarantine infected plants and reapply diluted neem oil every 7-10 days until there are no signs of pests or infection. For prevention, you can apply every 14 days.
Can You Use a Soil Drench Method?
You can also apply neem oil as a soil drench rather than spraying it on foliage, but some indoor gardeners prefer not to. This systemic pesticide method takes longer to become effective, which may not be optimal if you already have an infestation on your houseplants.
It is also difficult to test your plant’s response to neem oil with soil drench like you can with a foliar spray.
Additionally, neem oil as a soil drench can harm beneficial microbes in your plant’s soil. Therefore, it cannot be applied too often (need to wait 3-4 weeks between applications).
Neem Oil Frequently Asked Questions
Does Neem Oil Harm Beneficial Insects?
You might occasionally bring your houseplants into your yard and treat them for pests while outside. Fortunately, neem oil has minimal effects on most beneficial insects.
Unless directly sprayed on them, neem oil reportedly does not harm ladybugs or adult pollinators. However, it can harm pollinator larvae that are living on outdoor plants.
Common pollinators include moths, bees, butterflies, and wasps.
Do I need to rinse off neem oil from my houseplants?
For waxy-leaved houseplants, there is no need to rinse neem oil off of your plants. Do keep them out of direct light once neem oil is applied since this may cause the leaves to burn.
For indoor plants that regularly receive some direct light, keep them shaded for several days after applying neem oil. Then rinse them off before returning them to their former location. Be sure to re-treat them regularly until the pests are gone.
If I do not see pests after the first neem oil application, do I still need to reapply it?
Yes, they can easily be hidden, and treatment requires more than one application.
Additionally, pests can be tricky, like thrips, for example. While you may have killed the thrip larvae, the adults can still be present on your other plants and move back to the plant you just treated.
What houseplants should I not spray with neem oil?
Don’t apply neem oil to newly transplanted young plants, as it can damage the fragile plant.
You should also avoid using neem oil on plants that are already stressed. If you have a houseplant already stressed from a heavy pest infestation, you can try treating it with neem oil, with the understanding that the plant may or may not survive.
In addition, be cautious with plants that have velvety leaves, such as the Philodendron Micans and Alocasia Black Velvet. Some velvety foliage does not respond well to neem oil (or any kind of oil on the leaves). With these plants, you should test the product on one leaf for 24 hours before applying it to your entire plant.
If your plant is sensitive to neem oil, you can try rinsing pests off the plant manually with distilled water and drying the leaves immediately. Applying neem oil to their stems is usually harmless since stems aren’t textured like the leaves.
Benefits of Neem Oil for Indoor Plants
Cold-pressed neem oil can treat a wide variety of houseplant pests and also serves as a preventative treatment. It kills spider mites on contact and interrupts the life cycle of harmful insects like thrips and aphids. In addition, neem oil stops the spread of most fungal infections.
While neem oil is not entirely safe in all situations, it is safer to use around the home than chemical pesticides. Neem also puts less stress on your plants than most chemicals, and it provides natural pest management.