Is Neem Oil Effective for Cannabis Pests? Is it Safe?

Published Feb 02, 2024

by Nebula Haze

Are you battling pests or bugs in your cannabis garden, but don’t want to use harsh chemicals? Enter Neem Oil, which may be the #1 most popular organic pesticide in the world. In our surveys, neem oil is the most common insecticide used by cannabis growers, by far. That’s because neem oil effectively kills many cannabis pests, including aphids, crickets, grasshoppers, leafhoppers, leaf miners, mealybugs, spider mites, and thrips.

These leaves show damage from thrips, one of the many cannabis pests that can be treated effectively with neem oil.

Neem Oil is safe, organic and effective at many marijuana bugs as well as molds and fungus. Neem Oil is effective against the following marijuana pests:

*Neem oil does kill caterpillars, but if you’re struggling with a tough infestation, then try a “B.t Caterpillar Killer” spray, which is the most effective treatment for fighting caterpillars on cannabis plants.

What is Neem Oil?

Neem oil is a natural, organic pesticide derived from the seeds of the Azadirachta indica tree. In India, neem oil has been used for over 3000 years, with the first known mentions of neem oil in ancient Indian texts including the Atharva Veda, dating to at least 1000 BCE. Neem oil has a rich history deeply rooted in traditional medicine and agriculture.

For the cannabis grower, neem oil is a natural pesticide, fungicide, and miticide that effectively controls a wide range of pests. However, when used as directed, it doesn’t seem to harm most beneficial insects such as bees and butterflies.

Its effectiveness is largely due to Azadirachtin, an active component that makes the cannabis plant “taste bad” to pests, as well as disrupts pest reproduction and growth.

Neem oil also contains other compounds such as Salannin, Nimbin, Nimbidin, Meliantriol, and Nimbolide, which contribute to the overall effectiveness in neem oil as a pest deterrent.

Smell and Appearance: Neem oil is yellow to brown oil. The smell reminds me of garlic, but also is kind of earthy. Generally, I’ve found that when you mix neem oil with water as directed, it doesn’t have a crazy strong smell, though it has an unpleasant lingering sulfur smell.

Don’t get Neem Oil on buds. As far as safety when using on cannabis, you can use this product up until the day before harvest. But, as with any pesticide, don’t let any neem oil get on your buds because it will affect their final taste/smell, especially if it doesn’t have plenty of time to dissipate before harvest. If your plants are infested with bugs bad enough that the buds themselves need to be treated, it’s often time to harvest anyway.

Neem oil is an organic pesticide that is effective against many common cannabis pests, as well as mold and mildew.

Don’t expose plants to heat or light after neem oil. Use right before the lights go out (or the sun goes down) so it doesn’t burn your leaves.

Neem oil doesn’t hurt garden friends when used as directed. Ultimately, neem oil is an all-natural remedy that is very effective against many different types of bad bugs and mold, but won’t hurt humans, animals or most “good” bugs like bees, ladybugs, predatory wasps, etc.

Save money by using concentrate. If you want to save money, choose to get pure neem oil and mix with water in a mister (also called a “One-Hand Pressure Sprayer”). A mister is necessary to spray all the leaves evenly since neem oil and water separate easily.

Important! Some people have a bad reaction to Neem Oil:

Neem Oil is one of the most widely used, and most effective ways of combating pests in the grow room. When we surveyed our readers, it’s used by growers 8 times more than the next most popular pesticide, natural or not.

With that being said, there are people who have reported adverse reactions to buds grown using Neem Oil as well as Neem Oil itself. Additionally, some people can be allergic to Neem Oil, which can become a real problem when they smoke buds grown with Neem. Make sure you’re using Neem Oil safely by following a few simple guidelines:

Don’t use Neem Oil if you’re growing weed for someone other than yourself.
Don’t use Neem Oil if you’re growing weed for a medical patient.
Although this might seem obvious, don’t use Neem Oil if you’re allergic to it.
If you’re not sure, try a different pesticide that doesn’t contain Neem Oil, like Plant Therapy.
Here’s a list of all-natural cannabis pesticides including what pests each one is effective against.

Neem Oil is effective against:

Directions: How to Use Neem Oil on Cannabis Plants

Select Neem Oil: Choose 100% cold-pressed Neem Oil and mix with water in a sprayer if possible. It’s cheaper and may be the most effective version of neem oil for cannabis pests. However, Ready-to-Spray versions of Neem oil also work well.
Prepare the Mixture:
- Fill a one-hand pressure sprayer or spray bottle with lukewarm water.
- Mix in 2 teaspoons of Neem Oil per quart of water, or 2 tablespoons per gallon.
- Add a few drops of mild, non-detergent liquid soap or a plant-specific surfactant. This helps to emulsify the oil so it mixes evenly with water.
- Vigorously shake the mixture to ensure the oil and water are well combined.
Conduct a Test Spray: Before applying Neem Oil to all your plants, do a test spray on a small area. Wait 24 hours to check for any adverse reactions..
Apply During the Right Time: Spray your plants in the evening or when lights are off. Neem Oil can cause leaf burn if applied during high light intensity. Avoid application during high humidity to prevent fungal growth.
Application Technique:
- Spray both the tops and undersides of the leaves. These are common areas where pests like to hang out.
- Avoid over-saturating or soaking the plant, as all that extra moisture can invite fungus or mold.
- If needed, apply to the stems and soil to target soil-borne pests and larvae.
- Avoid Buds! Be cautious not to spray directly on the buds, especially close to harvest time, as neem oil will affect the taste and aroma of buds.
Reapply if Needed: Neem Oil is a gradual solution. Reapply every 7-14 days, or as needed, to maintain control over pests.
Monitor Plant Health: Keep an eye on your plants for signs of stress or pest activity. Adjust your application frequency and concentration accordingly.
Storage and Freshness: Store any unused Neem Oil mixture in a cool, dark place. Shake well before using again. However, a fresh mixture may be more effective.
Integrated Pest Management: Use Neem Oil as a component of a broader pest management strategy. Combine with other physical and biological controls for best results.

Last Thoughts on Using Neem Oil for Cannabis Pests

Neem Oil is a powerful, natural weapon in your cannabis pest control arsenal. It’s organic, easy to use, widely available, and effective at many cannabis pests, giving safety for your plants and peace of mind for you.

Got something to share? Contact GrowWeedEasy.com and let us know your thoughts on using neem oil for cannabis.