How to Safely Use Neem Oil On Herbs and Garden Plants 

Neem oil is a grower’s best friend in the fight against pests and diseases. 

It’s safe to apply all the way up until the day of harvest, providing an easy and effective year-round solution for disease and pest control on houseplants, herbs, and vegetable gardens.  

Neem oil leaves no harmful residues in the soil, efficiently suppresses and kills pests, and prevents fungal growth in plants.

If you’ve been asking, “can you use neem oil on herbs and garden plants,” this article will teach you how to do it safely and effectively.

What is Neem Oil?

neem tree growing in an indian village with cows feeding underneath it

Whatever type of grower you are, neem oil can be an excellent natural first line of protection against most common garden pests and diseases.

Neem oil is made from the seeds of the neem tree (Azadirachta indica), which is native to south Asia and the Indian subcontinent. 

As Indians traveled around the world in the twentieth century, many managed to bring the neem tree with them. It is now found in at least 30 different countries, mainly in tropical and subtropical regions of the world.

Neem oil has a strong, distinct odor and is yellow, greenish, or brownish in color. Since neem oil has antifungal and antibacterial qualities, it is an excellent foliar spray alternative for eliminating pests like whiteflies and aphids in your home garden.

It has also been used in herbal medicine for generations to treat a wide range of diseases and contains both fatty acids and glycerides. 

How Does Neem Oil Work?

aphid infestation on an outdoor plant

One of the most abundant active ingredients in neem oil appears to be azadirachtin, a complex chemical molecule. 

This substance is unique in that it has a large number of functional groups, which are sections of a molecule that can combine with other molecules, such as nitrogen, carbon dioxide, or, theoretically, some neurotransmitters.

According to research, azadirachtin can switch off the cells in bugs’ “brain cells” that enable them to experience the desire to eat, causing them to die of starvation. 

Neem oil also includes a plethora of other components, which may explain the insecticidal abilities of neem oil to address a wide range of pest infestations, illnesses, and other plant health issues.

Does Neem Oil Kill Beneficial Insects?

bright yellow honey bee with black stripes pollinating a flower

Before we get into how to prepare a neem oil solution, it’s worth asking, “Can you use neem oil on herbs without killing beneficial insects?” 

Thankfully, the answer is YES!

Neem oil is safe for most pollinators, including bees, butterflies, moths, and wasps, and leaf hoppers. 

Because these insects do not consume plant foliage, the azadirachtin component in neem oil will not affect them.

However, neem oil can have extremely harmful effects on pollinators if it comes into direct contact with them. 

So, if you’re not cautious and spray neem oil on an entire plant when pollinators are working, you may unintentionally damage or poison them.

Is Neem Oil Safe for Humans, Pets, and Wild Animals?

brown earthworms on the ground near green plant growth

The Environmental Protection Agency determined that neem oil had no obvious negative impacts on humans, pets, or other wild animals. 

It solely kills leaf-sucking and biting insects and does not generate a dead zone surrounding indoor plants, ornamental plants (like the Monstera Thai Constellation), trees, or bushes, as certain synthetic insecticides do.

Unlike typical synthetic pesticides that kill earthworms, neem oil has the opposite effect by increasing earthworm activity. 

Several experts in India studied the effects of azadirachtin and discovered that neem oil improved the weight and ability of earthworms to reproduce and create castings.

Can You Use Neem Oil On Herbs?

potted basil growing in an indoor kitchen near the window

The application of neem oil is meant to cover leaves and stems and can be used to target destructive bugs lurking in a small area. 

The oil coating can induce asphyxia in certain insects and cellular damage in others. However, not all plants can gain from neem oil. Some plants simply don’t like it! 

For example, cilantro, basil, caraway, oregano, dill, and parsley should not be treated with neem oil

If these plants are bug-infested, it is best to use an insecticidal soap instead.

To avoid leaf tissue burns, use caution when spraying neem oil insecticide on edible plants such as arugula, lettuce, peas, and spinach. 

If you are not careful when spraying neem oil, even hardier plants with tough foliage can be burned. 

Moreover, try to avoid spraying on recently transplanted or stressed plants.

Neem oil is far more toxic to plant seedlings than mature plants. Neem oil usually won’t harm adult plants, though it may damage foliage and limit plant growth.

Additionally, neem oil can be carefully sprayed on fruit plants before harvest.

If you are harvesting within a week of using neem oil, it is best to pick only what is required and then spray the plants with neem oil. 

Make sure to carefully wash your plants with warm, soapy water.

Neem Oil Benefits and Uses 

aphid infestation on yellow leaves of garden plant

Whether it is a rose plant or rose succulent, many gardeners will use neem oil as a natural pesticide to control hundreds of diseases and insects on their favorite plants.

Mites, mealybugs, aphids, whiteflies, beetles, leafhoppers, leafminers, caterpillars, and other munching insects react strongly to it.

When applied precisely on soft-bodied insects, neem oil eliminates them efficiently. The oil coating suffocates them by blocking respiration. 

Because of its antibacterial qualities, it is also efficient against fungi and molds such as root rot and powdery mildew.

The most remarkable feature of neem oil is that it is absorbed by many plants through the plant roots.

The neem oil is then collected by the stems and leaves, so when a starving bug bites it, it gets a taste of the poisonous neem.

The systemic impact of neem oil varies between plants and is not always effective against all insects.

Still, it’s one of the explanations as to why neem is such a potent pesticide for both small organic gardens and industrial crops.

Let’s take a look at a few of the most beneficial use cases of neem oil.

Fungal Diseases

Fungal disease is one of the most common garden culprits, whether you are growing fruit trees or fruit plants, for example, pineapples, leafy greens, and herbs. 

Fungal diseases lurk in the soil, creep up on young plants, and even seek opportunities to hit on pruning shears. 

Once active, fungal diseases take advantage of plant vulnerabilities, leaving plants exposed to other infections.

Luckily, neem oil has been shown in laboratory and field testing to be a highly effective insecticide against fungi that cause plant problems.

In the studies, neem oil controlled the disease while causing no harm to the plants. 

Although its effectiveness on bean plants in the field was somewhat less remarkable, neem oil still decreased the severe fungal disease significantly while remaining cost-effective.

Powdery Mildew

Powdery mildew is a generic word that refers to various fungal species. 

It often spreads to cover most of the leaves, turning them yellow and causing them to fry.

In such instances, a neem oil soil spray acts as a systemic pesticide, destroying parasites as they penetrate the plant’s surface. 

Once the powdery mildew infection has been eradicated, offering your plant a monthly neem soil spray solution is a good idea to avoid recurring infections.

Spider Mites

Spider mites are difficult to observe until their populations grow large, and other signs of their destruction include brown patches in leaves where they have nibbled right through. 

By interfering with the production of growth hormones, the toxin azadirachtin found in neem oil stops spider mites from continuing toward the next life stage.

Leaf Spot (Black Spot)

Black spot is a fungus that causes circular, black spots with curled borders on leaves. 

Like other fungal plant diseases, neem oil spray can effectively eradicate black spot manifestation on plants.

Fungus Gnats

Fungus gnats cause plants to struggle with growth and keep them small. 

If you notice tiny gnats flying around your flower bed, you may have a fungus gnat infestation.

To treat fungus gnats, mix 10ml of pure neem oil with a liter of water and spray it on affected plants and plant soil, as fungus gnats live on potting soil and other container media.

Neem oil will also hinder the ability of fungus gnats to lay eggs.

Japanese Beetles

Japanese Beatles are voracious eaters, attacking over 300 different fruits and vegetables. 

If you have a Japanese Beatles infestation in your garden, spray it with neem oil every day for two weeks, then reapply as a preventative measure for the next two weeks.

Squash Bugs

A significant squash bug infestation can kill entire crops by substantially weakening the leaves. Since neem oil decreases feeding during the nymph stage, it is an efficient strategy to limit the damage.

Cabbage Worms

Spraying your plants with a neem oil mix regularly may make your plants less appealing to cabbage worms. 

However, if your plant is already infested, neem oil is unlikely to manage cabbage worm populations.

Scale Insects

If a scale insect invasion is extreme, it can be disastrous to fruits, perennials, shrubs, and houseplants.

By abundantly spraying all afflicted portions of your plant, you will allow the neem oil solution to suffocate the scale insects and kill them.

How much neem oil you apply should vary based on the severity of the infestation, and the beginning of an infestation is the best time to start applications.

How to Mix Neem Oil Spray for Herbs and Garden Plants

Commercial neem oil spray and other commercial products like cold-pressed neem oil and neem cake are available at most local nurseries and hardware stores. 

A handmade solution, on the other hand, is easy to produce and allows you to correctly measure the concentration and effectiveness of your mix. There are different ways to dilute organic neem oil mixtures, but we recommend the following method for creating the best neem oil. 

Follow the steps below to make your DIY neem oil mixture.

Tools and Materials Needed

  • Spray Bottle
  • Protective Gloves
  • 1 Gallon of Water (warm)
  • 2 Tablespoons of Pure Neem Oil
  • 2 Teaspoons of Mild Dish Soap
  • 1 Teaspoon of Peppermint Essential Oil (optional)

Steps to Mix a Neem Oil Solution

  1. Begin by adding a pure form of neem oil to a gallon of warm water. It’s important to ensure that you only use warm water because it leads to better emulsification.
  1. Next, add mild dish soap to the mixture. In case you are wondering, the mild dish soap here acts as an emulsifier. Because the hydrophobic neem oil and water do not combine easily, adding dish soap aids in emulsifying the mixture.
  1. At this point, you have the option to add peppermint essential oil. Although it is optional, the scent of peppermint essential oil can help prevent insects and provide the best results. If you don’t have peppermint essential oil on hand, you can substitute peppermint dish soap.
  1. Shake the gallon container a few times to make sure that everything is well-mixed. Once thoroughly blended, the mixture should appear slightly hazy and soapy.
  1. The mixture is now ready to use, and you may pour it into your spray bottle. Your DIY neem oil solution is most powerful within hours of being prepared and can be kept in a sealed container for up to four days.
  1. Spray the mixture on a daily to weekly basis. Spray the plant daily for up to a week for severe infestations, and always shake the sprayer canister before spraying to ensure appropriate mixing.

How and When to Apply Neem Oil on Herbs and Garden Plants

Spraying plants with neem oil solution regularly can be a great way to avoid insect pests and even eliminate existing infestations. 

With the help of this potent oil, your plants may survive and thrive and flourish with just a small spritz once or twice a day.

The good news is that because it can remove pests at any point in their life cycle, neem oil can be used throughout the growing season. 

It can keep pests at bay as well as eliminate bugs that are already present through an invasion.

It is essential to remember to only use it in the early morning and at night. The combination of direct sunlight and neem oil might burn the plants if used in the middle of the day.

Also, remember that neem oil is primarily used as a preventative measure in your vegetable garden, so it is most effective during the planting season. 

Also, conduct a patch test on a robust plant with a lot of fresh leaves to test your neem seed oil mixture.

Neem Oil Takeaways

Neem oil extract is a plant-based pesticide that is widely available and can be found in most big-box supermarkets, online retailers, and even tiny local nurseries.

Still, you can mix a unique home solution to precisely target your needs. You can even buy neem seeds to grow yourself if you are interested. 

Since ancient times, the neem tree has been revered as a sacred treatment and an important component of Ayurvedic medicine. 

In the garden, neem oil has strong insecticidal properties, making it an excellent organic solution for managing a range of pests on outdoor plants.

It is also a bio fungicide and an efficient pest management solution for over 200 types of pest species. 

Many people consider it a must-have in their gardens, and we strongly advise you to include it in yours as well. 

It is especially useful to organic gardeners, as it does not compromise your plants or crops in organic gardening operations. 

So, can you use neem products on herbs? Of course!

Like any other pesticide, though, neem oil products can be harmful to plants and beneficial insects if misused. 

Wearing protective clothing is a good thing to do when applying the neem oil pesticide because the intense formulation might irritate skin or other sensitive parts of your body. Allergic reactions are also possible.

Happy growing!

Be sure to check out our other articles on DIY projects to keep a happy and healthy garden!

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