spraying neem oil on indoor plant to keep gnats, scale and other pests and bugs away

How to Use Neem Oil On Indoor Plants

If you’ve only heard of indoor gardeners using Neem oil to treat bugs and pest infestations on their indoor plants and you’d like to learn how to properly mix or apply Neem Oil to your own plants, this guide will explain exactly that. Knowing how to use Neem Oil on your indoor plants is a wonderful addition to your growing knowledge of indoor plant care.

How to use neem oil for indoor plants? Mixing and applying neem oil on your indoor plants is mostly done as a pest control measure. Neem oil can be extremely effective at treating pests including, scale bugs, thrips, whiteflies, aphids, fungus gnats, mealybugs, and spider mite infestations among many others.

In today’s in-depth article, I’ll answer all your most burning questions about using neem oil. By the time you’re done reading, you can confidently use this product, even if for the first time, to benefit your indoor garden! 

What Is Neem Oil?

You don’t like to apply any product to your indoor plants without learning more about it first. That’s why I thought I’d start by describing what neem oil is and where it comes from.

Neem oil is sometimes referred to as margosa oil, but you’ll most commonly hear it called neem. It’s a type of vegetable oil sourced from the Azadirachta indica or neem tree. 

This tree grows on the Indian subcontinent but prefers tropical environments and thus has been propagated elsewhere. 

The main ingredient in neem oil is azadirachtin, which is a type of triterpenoid, aka a chemical compound class with three units of terpene. 

The other triterpenoid in neem oil is nimbin. Let’s talk about what both these ingredients do.

  • Azadirachtin: Initially tested on desert locusts, azadirachtin has been proved to treat more than 200 insect species (and counting) as a growth disruptor and antifeedant. 
  • Nimbin: A lot of neem oil’s benefits come from nimbin, which is an antiseptic, antihistamine, fungicidal, antipyretic, and anti-inflammatory triterpenoid. 

How to Mix Neem Oil for Indoor Plants

If you’ve used fertilizer for your indoor plants (and I assume you have), then you know you usually have to dilute it with water first.

It’s the same case for neem oil, but water and oil don’t exactly play nicely together. That’s why you have to emulsify neem oil first.

You have two options for this, liquid soap or silica. Let’s go over both these options now.

Liquid Soap for Neem Oil Emulsification

The more common ingredient of the two, liquid soap is a good neem oil emulsifier. 

If you’re going to use liquid soap to mix with your neem oil, I highly suggest that you use a liquid soap scented with essential oils such as peppermint, as that will only make the neem oil more effective at killing insects. 

Silica for Neem Oil Emulsification 

Potassium silicate or silica is another method for emulsifying neem oil. 

When used in neem oil, silica can benefit your plants in a myriad of ways. The ingredient will build stronger cell walls that might manifest in longer plant stalks.

The plants will also have better resistance to drought and stress.

The silica and neem oil stick on the plant’s leaves, reducing the risk of insects and fungal disease. 

Whether you’ve chosen liquid soap or silica to emulsify the neem oil, you only need a teaspoon of silica per each tablespoon of neem oil. Stir the ingredients thoroughly until they become thick and creamy. 

Should You Pour or Spray on Neem Oil?

spraying neem oil on newly propagated plants to stop pest infestation

You’ve got some neem oil ready to go, but this will be your first time using the stuff. Should you pour it directly on your plants or spray it on them?

It’s almost always better to carefully spray neem oil on your plants rather than pouring it on them. 

I’ll talk later about whether neem oil can negatively impact plants, but for now, here’s a little hint: it can. Thus, you don’t want your application to be all willy-nilly.

Another benefit of spraying rather than pouring on neem oil is that you’re being less wasteful.

Neem oil isn’t particularly expensive (although that depends on the brand and the product), although I wouldn’t go so far as to call it cheap either. 

You don’t exactly want to waste what you got and pouring the neem oil on will definitely do that. 

Using Neem Oil for Pest Control

By far, the most popular usage of neem oil is to control pests. 

Many indoor plant species attract pests; it’s simply the way of things. 

These pests are more than mere annoyances and can cause significant damage to your plants, sometimes even killing them if an infestation gets severe enough. 

Many indoor gardeners look high and low for an easy and effective method for insect removal. That’s exactly what neem oil is.

Here’s an overview of the most common indoor plant pests that neem oil can kill. Keep in mind this product is effective on hundreds of insect species overall!

Spider Mites

The microscopic spider mite will make its home underneath a plant’s leaf. There, it will suck up the sap and build silken webs.

To treat spider mites in your indoor garden with neem oil, mix a liter of lukewarm water with a half teaspoon of neem oil and a teaspoon of mild liquid soap. 

Put the ingredients in a spray bottle, mist the undersides of the plant leaves, and repeat as needed until the mite are gone.

Fungus Gnats

Although their lives are short, fungus gnats can wreak some major havoc for the short time they’re on this earth. If they swarm, fungus gnats can get into the roots of your plants!

Ward off fungus gnats with a liter of water, a teaspoon of liquid soap, and a teaspoon of neem oil in a spray bottle.


A type of scale insect but without armor, mealybugs prefer warm, moist conditions like those that tropical plants enjoy. 

Mealybugs can easily spread plant diseases across your indoor garden and seriously damage your plant as the insect sucks up the leaf sap.

You’ll need a liter of water, a teaspoon of liquid soap, and half a teaspoon of neem oil in a spray bottle to combat mealybugs once and for all.

Scale Insects

Another type of unwanted plant pest, scale insects can invade any indoor plant rather quickly, which is terrifying to witness. 

How to Treat Scale on your Plants by Spraying Neem Oil on the Plant

Combine a liter of water, a teaspoon of liquid soap, and half a teaspoon of neem oil. Put it all in a spray bottle and shake well. Spray where you see the scale insects and repeat as necessary. 

It’s common to have to repeat this every 2-3 days until the pests are completely gone.

I’ve written an entire article dedicated to dealing with scale insects on indoor plants titled: Scale on Your Plants? How to Control These Insects


The winged, slim insect known as thrips has various mouthparts for drinking plant sap. They can spell death for a plant in a short time so treating them as soon as you see that they’ve infested your plant is paramount.

How to Treat Thrips on your Plants by Spraying Neem Oil on the Plant

By mixing a liter of water, a teaspoon of soap, and a half teaspoon of neem oil you’ll have the perfect mixture of neem oil to spray the affected portions of your plant and rid it of thrips.

It’s worth mentioning that I always mix enough to last multiple treatments.


Resembling grains of rice that have made a home on the underside of your plant leaves, whiteflies are quite an unwelcome sight. They can fly, which makes it easy for them to get from plant to plant.

A liter of water, a teaspoon of soap, and a teaspoon of neem oil in a spray bottle will do the trick, warding off whiteflies. 


Last but certainly not least are aphids, which are teeny-tiny insects that suck up sap and come in a rainbow of sickening colors. 

This time, you need a liter of water, four teaspoons of liquid soap, and one teaspoon of neem oil. Shake the ingredients in a spray bottle and then go to town. 

How Often to Use Neem Oil on Indoor Plants 

You’re happy to say that the neem oil worked. Your plants are pest-free, and better yet, the oil produced an appealing sheen on the foliage that you find quite appealing. 

Now that your plants are healthy, do you have to continue using neem oil?

Indeed, it’s recommended that you apply the stuff to indoor plants every two to three weeks. 

Even if you don’t currently see any insect infestations on your plants, in the meantime, neem oil works as a preventative. 

You already know the health havoc that pests can cause, so being able to prevent an infestation is best! 

Can Neem Oil Hurt Indoor Plants? What About People or Pets?

Neem oil, although it’s sourced from plants itself, is still a pesticide at the end of the day. 

You should never use the stuff carelessly, be that around your plants, pets, or other human members of the household.

To wrap up, I want to talk about whether neem oil is harmful to the above parties. 


You would hate to put your indoor plant under any more duress by trying to treat them, but sometimes, when using neem oil, that’s precisely what can happen.

The stuff is only effective when a plant is covered but overdoing it on the neem oil does more harm than good.

Plants have stomata in the leaves that allow the plant to take in air. When the plant is oversaturated with neem oil, the oil plugs up the stomata. The plant can essentially suffocate. 

That’s not all.

Neem oil can also burn plants, especially plants that are stressed (or are recovering from stress), newly transplanted, or young. You should avoid applying neem oil on these plants. 

If you’re going to use neem oil, limit its application to either in the morning or the evening. An afternoon application of the stuff, in combination with the brighter afternoon sun, can scorch your plant’s foliage. 

The best way to use neem oil on an indoor plant is to spot-test it on a small portion of the leaves. If the plant is okay after 24 hours, then you should be able to use more neem oil. 

Just do watch your quantities. For some plants, too heavy of a dose of neem oil can be deadly. 


What about your favorite four-legged friends like your dog or cat? If they get into your indoor garden while you’re treating it with neem oil, what would happen?

Fortunately, neem oil is not toxic to pets. The flavor of the stuff is also so bitter that if any pet got too curious and ingested some, they would immediately regret it.

Even still, take precautions to keep your pets away from your indoor garden. It’s for the best! 


You should always keep neem oil locked away when not in use if you have young children in the house. The plant treatment may be toxic and can cause very damaging side effects to young children and babies.

These include severe brain ischemia, encephalopathy, kidney failure, seizures, and metabolic acidosis. 

Adults needn’t worry so much, as neem oil has low toxicity for humans. Even still, to be safe, wear gloves and protective equipment when mixing and applying neem oil.

You certainly don’t want to get the neem oil in your eyes or on your skin, as the oil is irritating. 

Be sure to flush out neem oil if it gets in your eye and wash it off the skin immediately. 

Where to Buy Neem Oil?

Now that you understand the chemical composition of neem oil better, you might be interested in picking some up. Where can you find this plant product?

All sorts of places, really! Here’s where to start shopping.


If you have a favorite online gardening supply store, I bet they carry neem oil. You can also buy all sorts of neem oil products from online retailers such as Amazon. 

Having neem oil shipped right to your door is advantageous since it’s quick and efficient.

I’ve been using the Organic Neem Bliss brand, you can find it here on Amazon.

I only have to buy a 16-ounce jug of neem oil once every other year.

Garden Supply Store

If you don’t mind shopping in a store, you can also pop into your local garden supply store and check around. More than likely, the store should stock neem oil.

You can select from different brands that make neem oil products as well as different quantities depending on how many plants you need to treat. 

Home Improvement Store

Although you might not initially think so, home improvement stores often carry neem oil in the garden supply section. 

From Lowe’s to Home Depot and other big names in home improvement, they’ve usually got neem oil in stock.

You can shop in the store or order neem oil for online delivery. 

General Retailers

General retailers with a garden supply section should also offer neem oil such as your local Walmart. 

Keep in mind that if you have the time and the means, you can also make neem oil at home! 

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