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Neem Oil for Killing Cannabis Pests

Neem oil for cannabis

Cultivating cannabis for medicinal or recreational purposes is a complex endeavor that demands meticulous attention to detail. Nevertheless, pests provide a substantial risk during cultivating. Spider mites and aphids can rapidly infest cannabis crops, leading to productivity and quality. Neem oil, a natural alternative, offers hope to cannabis growers worldwide. Neem oil, derived from the seeds of the Indian neem tree (Azadirachta indica), has an extensive historical record of application in the fields of agriculture and medicine. The compound azadirachtin found in it has a complex composition and acts as a powerful insect growth regulator. It inhibits the development of pests, making it highly effective against them. Neem oil acts as a deterrent to pests and is environmentally neutral, making it well-suited for sustainable production.

Understanding Neem oil

Neem oil is derived from the neem tree, which is formally known as Azadirachta indica. Due to its natural insecticidal properties, it is often preferred by organic farmers as a pest management method. Neem oil has proven advantageous for plant preservation for ages, and it is still being employed by contemporary producers on both small and large levels. When applied as a spray on the leaves, the biopesticide shows effectiveness against a wide range of pests and pathogens, such as insects, fungi, and viruses. A key constituent of neem oil, known as azadirachtin, acts as an antifeedant and insect development regulator by suppressing the release of a hormone that promotes the transition of insects from the larval to the pupal stages.

Oil extraction from the neem tree’s seeds entails a series of essential procedures. Initially, the process involves the collection of seeds from fully grown neem trees and then extracting the kernels after breaking open the seeds. The professionals subject kernels to pressing using industrial processing equipment or traditional wooden hand presses called ghanis. Neem seeds contain a significant amount of oil, with yields reaching up to 50% of the kernel’s weight. Some bottled neem oil formulations may include emulsifiers to mix the oil with water before application appropriately.

Common cannabis pests

Neem oil is effective against several cannabis pests. These are some of the pests neem oil can control:

  1. Spider mites: They can easily infest cannabis plants, causing discoloring, webbing, and stunting growth. Disrupting their life cycle with neem oil reduces numbers and prevents further damage to your plants.
  2. Aphids: Aphids feed on cannabis sap, weakening and infecting the plant. Neem oil acts as a repellent and asphyxiant, deterring aphids from consuming and finally leading to their demise.
  3. Whiteflies: These pests threaten cannabis harvests. Neem oil coats their respiratory system, preventing breathing and killing them.
  4. Thrips: These small insects destroy and spread illnesses on cannabis leaves. Neem oil hinders their ability to feed and impairs their growth and development.
  5. Fungus gnats: In damp soil, fungus gnats lay their eggs and feed on organic debris and plant roots. Neem oil repels and kills fungus gnats, blocking larval development.

Application tips for neem oil

Below are tips for applying neem oil to your plants:

Test Patches First

Your plant’s reaction to neem oil is unpredictable, no matter how careful you are. Although many consider neem oil to be safe, your cannabis plant may not respond well due to genetics or the environment. As a precaution, do a patch test on an old leaf and wait a day before using it on the whole plant. If your cannabis plant’s leaf has blemishes, discoloration, or other indicators of stress, neem oil may not work.

Get a Good Spray Bottle

Many growers buy any spray bottle, including salon ones! Do not do that. Instead, use a garden spray bottle meant for gardening. Their convenience and quality make them better than traditional spray bottles.

Spray neem oil properly

Drenching the plant and buds in neem oil is unnecessary and can damage the buds. Instead, it would be best if you had a more targeted strategy. Spray neem oil where pests are, especially under foliage, where most bugs hang out. Get comprehensive coverage without soaking your plant in neem oil when spraying. Over-spraying the neem oil can create minor burns on the plant. The plant should be mildly wet after neem oil application. If you have an indoor setup, apply neem oil during the dark hours and turn the fans off. You can turn off the lights for an hour. Avoid light and strong breezes when using neem oil to avoid mild burns and other issues.

Using Neem Oil to Prevent Cannabis Pests

To prevent pests from invading your cannabis grow, apply neem oil throughout the vegetative stage three weeks before harvest. It works best as a weekly foliar spray on cannabis plants.

Do not spray buds and seedlings

It is not advisable to spray neem oil on buds. The taste of neem oil during blooming can be unpleasant when smoked; hence, many expert growers advise against it. You can wash the buds, stems, and leaves before harvesting, but neem is bitter, and you may not like its smell. When smoked, neem’s powerful smell can stick to the buds and leave a minty, pungent taste.

If you need a pesticide during flowering, try baking soda or alcohol with water instead of neem oil. Small seedlings cannot handle neem oil well; therefore, do not use it. Although safe for established plants, neem oil is too harsh for seedlings. You can use neem oil after a month, but start with a weaker solution.

Nighttime Spray

Only apply neem oil as a foliar spray during dark hours to maximize effectiveness and avoid plant light burns. Beneficial insects are less active on the plant at night so that you won’t spray them. Spraying at night keeps the solution on the plant longer before drying off, making it more effective.

In addition to avoiding the use of neem oil on young seedlings and flowering cannabis, there are other situations where it is not advisable to apply it to your cannabis plant, including the following:

  • Refrain from applying neem oil to plants that have recently experienced nutritional deficit, overfeeding, or water-related strain until the plant has fully recuperated.
  • To prevent light or heat burns on the cannabis plant, refrain from spraying the solution when the temperatures are too hot or cold or when the lights are on. The optimal time to apply neem oil to cannabis plants is during the evening hours, specifically after sunset, when temperatures are approximately 20°C or 68°F.
  • Avoid applying neem oil on your cannabis plant at least three weeks before harvesting to prevent any modification of the buds’ inherent flavor characteristics.
  • If your plant is experiencing a pest infestation at this time and you are seeking a prompt remedy, you can select from a range of neem oil options that will protect your plant without compromising the flavor profile of the buds.

How to dilute neem oil before application

Cold-pressed neem oil is highly potent and requires dilution before use. For smaller applications, you will need a one-quart spray bottle and a one-gallon pump sprayer for larger applications. It is important to always adhere to the precise mixing instructions provided on the product label. To enhance the mixture of water and oil, use a small quantity of horticultural or plant-safe liquid soap as an emulsifier in the suspension.

Begin by combining the water and soap. To make a gallon of soapy water, add one teaspoon of soap. If you are using a quart spray container, use only ¼ teaspoon of soap. After mixing the water and soap, add a small quantity of neem oil, precisely one to two tablespoons per gallon of water, or one to two teaspoons per quart of water.

The solution preparation for soil drenches should follow the same procedure as for foliar sprays. However, it is essential to note that a larger quantity of solution may be required, depending on the specific purpose. Keep in mind that neem oil degrades quickly. Avoid combining more than the desired amount for a single use, and prepare a new mixture for subsequent treatments.

Although the smothering properties of oil may initially reduce the number of pests, the effects of azadirachtin on insect feeding and development are not immediately evident. Therefore, we should not lose hope if the problem is not resolved immediately. Instead, observe a gradual reduction in the pest population over time and regularly reapply neem oil every week until you observe a noticeable enhancement.

Benefits of using neem oil on cannabis plants

Growers seeking eco-friendly pest management choose neem oil for cannabis plants for its many benefits.

Eco-friendly and natural

Neem oil is extracted from the seeds of the neem tree (Azadirachta indica), a plant indigenous to the Indian subcontinent. It is natural and free of synthetic chemicals and poisons in traditional insecticides. This enhances the safety of neem oil for the environment, producers, customers, and beneficial insects such as bees and ladybirds.

Efficient pest management

Neem oil is renowned for its wide-ranging effectiveness against spider mites, aphids, whiteflies, and thrips, which are common pests for cannabis plants. Azadirachtin exerts an influence on the eating, moulting, and reproduction of insect pests. This practice reduces pest populations and safeguards cannabis crops.

Proactive Measure

Neem oil not only repels bugs but also safeguards cannabis plants against future attacks.

Regular application of neem oil sprays protects the plant’s surface from insect feeding and egg-laying.

Growers can enhance crop protection and sustain plant health by employing neem oil in their pest management practices.

Free from residue

Unlike synthetic pesticides, neem oil rapidly decomposes in the environment, resulting in minimal residue on plant surfaces. Neem oil treatment of cannabis plants eliminates pesticide residues, hence enhancing the safety and quality of the final product. Neem oil undergoes decomposition, resulting in the formation of organic compounds that enhance the quality and productivity of the soil, so boosting its overall health and fertility.


Neem oil can be used by farmers through foliar sprays, soil drenches, or root drenches to control pests in different growth conditions. Neem oil applications can be tailored by growers to suit the specific needs of indoor, outdoor, and greenhouse cannabis growing.

Compatible with Integrated Pest Management (IPM)

Neem oil is used as a component of integrated pest management (IPM) strategies that prioritize thorough and sustainable methods for controlling pests. By integrating neem oil with cultural, biological, and crop rotation IPM strategies, growers may effectively decrease the use of synthetic pesticides and achieve sustainable pest control in the long run.

Drawbacks of neem oil

While neem oil has several benefits for pest management in cannabis, it is important to acknowledge the potential drawbacks or limitations associated with its use. The drawbacks of utilizing neem oil on cannabis plants are as follows:

Risk of phytotoxicity

Neem oil can produce phytotoxicity in cannabis plants, especially when used in excessive quantities under specific circumstances. Phytotoxicity can result in leaf scorch, drooping, and inhibited growth, leading to a decline in plant vitality and vigor. This issue may be due to the incorrect dilution or application of neem oil, particularly in high temperatures or direct sunlight.

Potential Resistance

Overusing neem oil can lead to the development of insect resistance, which diminishes its efficacy in the long run. The biochemical features of neem oil may decrease the vulnerability of pests to its active ingredients, such as azadirachtin. Therefore, if neem oil proves ineffective in pest management, gardeners may have to resort to alternative approaches. By incorporating neem oil into a rotation with other pesticides or implementing Integrated Insect Management (IPM) strategies, it is possible to decrease resistance and uphold effective insect control.

Effects on Beneficial Insects

Although neem oil is generally harmless to beneficial insects such as bees, ladybirds, and predatory mites, its wide-ranging pest control properties can potentially harm unintended organisms. Organisms that come into contact with neem oil spray may experience mortality or reduced reproductive capabilities. Interfering with the natural mechanisms that manage pests could potentially exacerbate pest issues in the long run. Growers should refrain from using neem oil during periods of high activity or employ customized treatment techniques to reduce unintended exposure to non-target organisms and save beneficial insects.

Using neem oil to promote sustainable cannabis cultivation

Neem oil is a potent and versatile solution for insect control and promoting environmental sustainability in cannabis cultivation. It aids growers in combating prevalent pests in cannabis cultivation and establishing a more balanced connection with the environment, leading to healthier plants and increased yields while reducing the reliance on synthetic chemicals. With the evolution of the cannabis market, the significance of organic and ecological growing practices increases. The effectiveness of neem oil against a diverse array of pests and its little impact on the environment make it an essential component of ethical cannabis growing. It enables growers to satisfy the expectations of discerning consumers while upholding environmental stewardship. Growers enhance the sustainability of the cannabis sector by employing neem oil to safeguard their crops.


Picture of Janice Bernstein

Janice Bernstein

Janice has been on the cannabis scene for many years now, though she tends to keep to herself and might fly under the radar for many, even those well-versed in cannabis growing. Her writings on different methods of watering cannabis helped bring the use of reverse osmosis water to the forefront of cannabis gardening. About this Author

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