How To Apply Neem Oil – Do’s and Don’ts

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Neem oil is practically a necessity for many gardeners and plant enthusiasts. This natural substance is from the pressed seeds of the neem tree (Azadirachta indica) native to India.

What is neem oil used for?

It contains an active ingredient in the oil called Azadirachtin that repels and kills pests like aphids, whiteflies, spider mites, thrips, mealybugs, caterpillars, Japanese beetles, and other grubs. 

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It also effectively controls fungal diseases and other problems like anthracnose, blight, leaf spot, black spot, scab, rust, and powdery mildew.

In this article, we’ll explore all aspects of neem oil on plants, including the uses for neem oil and neem oil benefits.

Is Neem Oil Safe For Humans, Pets and Plants?

When used correctly, neem oil is safe for most plants, pets, and humans.

If you have children at home, you might also ask, Is neem oil safe for babies?

Neem oil should not be used directly on or around babies without the guidance of a healthcare professional.

While neem oil is generally considered safe for topical use in adults, it may cause adverse reactions or skin irritation in infants or young children.

Moreover, neem is used in cosmetics, medicines, and even toothpaste.

However, as with all products, there are times when neem oil isn’t the best option.

For this reason, you should always consider the rules on neem oil usage before attempting to apply it.

How To Apply Neem Oil

You can use neem oil as a natural pesticide and repellant for both indoor and outdoor plants.

However, it’s important to know how to properly mix neem and apply neem oil, as improper use may harm beneficial insects, aquatic life, or even your plants.

Thankfully, the rules of neem oil for plants are pretty simple and easy to remember.

Where NOT to Use Neem Oil

Neem oil is safe for many plant species but doesn’t distinguish between beneficial and harmful insects when used topically as a foliar spray on plants.

Neem oil works by having the ability to disrupt insect hormones and can also create health risks under certain circumstances.

Here’s a key list of when you should avoid using certain neem products:

  • NEVER use foliar sprays during the day, as bees and other beneficial insects and pollinators may contact it. Read Neem Oil and Bees.
  • NEVER use neem foliar sprays near a beehive, as the wind may carry droplets to the nest.
  • NEVER use neem products near water features that contain aquatic life. Neem is mildly toxic to many fish and amphibian species. Neem products are banned in Canada and the UK.
  • AVOID applying when children or pets are around, as they may ingest the neem beyond safe quantities.
  • NEVER leave neem products around small children, as it has been known to cause seizures or other side effects when ingested by young children, although these risks dissipate as the child ages.
  • AVOID coming in direct contact with neem products if you are pregnant or breastfeeding, as it can cause complications or even miscarriage and may also contaminate your breast milk.

Which Plants Don’t Like Neem Oil? Testing Plant Tolerance

Is Neem Oil safe for plants? In general, YES! But you should always test your plants before applying neem products. Some plant species have a natural intolerance. Check out our article on “What plants not to use Neem oil on” to learn more. 

Meanwhile, plants that should be tolerant of neem may have a sensitivity or allergic reaction, just as humans sometimes do to peanuts or other normally innocuous products.

Testing your plant for Neem Oil Sensitivity

  • Apply a very small amount of your Neem solution to an isolated spot on your houseplant.
  • For neem oil spray, apply to a single leaf, while a few drops of soil soak may be added to a plant’s stem near the base using an eyedropper.
  • Wait for 24 hours for the neem oil to work, occasionally checking for any negative reaction.
  • If the plant shows signs of sensitivity, avoid using neem products on that plant.
  • However, if there’s no reaction, you may go ahead with the treatment.
  • Some guides suggest testing before every use, while others consider it a one-and-done.
  • We suggest personal discretion in how often you test, as plants may gain or lose sensitivity over time, but you should try to test at least annually.
  • Moreover, always follow the instructions on the product label.

When to Apply Neem Oil

As mentioned above, neem insecticide can harm beneficial insects and bad ones if applied at the wrong time due to its chemicals.

To avoid harming bees, ladybugs, and other garden friends, always apply your needed treatments at dawn or dusk.

This time is when butterflies, moths, bees, and other bugs are least active.

Neem foliar sprays only take 45 minutes to 1 hour to evaporate, so they’ll be gone by the time these helpers start their daily (or nightly) routine.

This also gives neem soil soaks time to absorb into the ground.

Another reason to apply at these times is to avoid sunburn on indoor or outdoor plant surfaces.

Because neem oil is mixed with warm water, applying when the sun’s up increases the risk that the sunlight will scorch the leaves.

While neem is generally non-toxic, you don’t want to get a mouthful when eating fresh produce.

To avoid this, always apply the neem at least one day before harvesting.

It is also best to apply soil soaks when the plant is thirsty so you don’t accidentally overwater.

Applying Foliar Neem Sprays

Foliar Neem sprays are more involved than soil soaks and must be applied more frequently.

You can dilute concentrated neem oil with water and add liquid soap. After that, pour the mixture into a spray bottle.

Spray the entire plant, being sure to get the undersides of every leaf and any crevasses. Ensure that you spray the leaves’ undersides where pests, larvae, and eggs can hide.  

During pest infestations, you must reapply every other day for 14 days.

As a preventative, you will need to do one application every 14 days.

Applying Soil Soaks

Soil soaks are much easier to apply, especially with larger plants.

Related: More on Watering Plants with Neem Oll

Pour 2-4 cups of the mixture (or more for larger plants such as citrus trees) directly onto the ground around the plant’s base.

Try to avoid splashing the stem, trunk, or any exposed roots, and aim to cover the ground in a radius so you can cover most of the root area.

Neem soaks get absorbed into the plant, so they last a lot longer.

Apply once every 21 days for both infestations and as a preventative.

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