How to Use Neem Oil for Cannabis Plants [Organic Pest Control]

Lots of cannabis cultivators want their grow operation to be as natural as possible, which makes neem oil a must-have product. It can be both a preventative tactic and a cure for numerous fungal and insect problems. Plus, it can minimize the impact of the pest population without harming beneficial organisms. This helps you keep a balanced ecosystem on your farm.

Many synthetic fertilizers and nutrients claim to be all-natural, but unfortunately, many are far from it. There are authentic organic alternatives, like diatomaceous earth, that work, but they aren’t nearly as effective as neem oil.

Research shows that there is a huge difference in the adverse effects that may come from chemical-laden products. So, even if you plan to stay 100% organic, it’s still worth learning the ins and outs of the trade that will help you to naturally cultivate and protect a plentiful crop.

Finding non-toxic, safe pesticides for growing plants and ones that actually work can be rather challenging. Many of us want to protect the environment, our food, and our families, but most non-man-made chemicals out there aren’t all that effective.

There is, however, one exception: neem oil.

What Is Neem Oil?

Neem oil is a natural and safe insecticide, making it a great tool for organic cannabis growers. It’s harvested from the neem tree and is effective against many common cannabis pests. The neem tree produces a thick sap and grows predominantly on the Indian subcontinent. It has been used in India for centuries and is now the de facto treatment for organic farmers worldwide.

Neem oil is made by pressing the oil out of the fruits and seeds of the neem tree. It’s a pure vegetable oil that has all the benefits of the tree’s natural pest resistance. The neem tree is notorious for the powerful effects of the concentrated triterpenoids and triglycerides contained within its oils.

What makes neem so unique is that it’s 100% natural and safe to use. It’s non-toxic to humans and animals, and if you use neem oil properly, there are no negative effects on plants.

Neem oil is known to be very effective against many of the common cannabis pests but works especially well against soft-bodied insects like aphids, spider mites, and whiteflies. It’s also fungicidal and effective against mold, fungi, and mildew.

How Neem Oil Works

Neem oil is not an instant fix. Many chemical insecticides kill pests right away, but neem oil doesn’t work on contact. Instead, when applied, it creates a hostile environment for reproduction and, over time, depletes the population.

The oil enters the insects and interferes with their reproductive system. Furthermore, the oily coating on the leaves prevents the viability of eggs. The crop’s environment becomes toxic to the pests, and after a few generations of low birth rates, the population collapses.


Typically, growers apply neem oil to plants in a diluted form as a foliar spray. It’s worth noting that many neem oil products give users instructions to dilute the spray with water only.

However, this is not good advice!

Oil doesn’t dissolve well in water. To spray your plants with neem oil, the oil needs to break down so that it mixes with water and forms an emulsion. Some growers suggest adding a few drops of liquid soap to the water before you add the recommended neem oil amount.

Although this may work, it’s probably best to look for special insecticidal soap (“potassium soap”) to create your neem and water solution.

Neem Oil for Organic Cannabis Care

Neem oil is a fantastic way for organic cannabis growers to get a pest- and fungus-free garden. Incredibly, it only targets bad bugs in the garden and leaves good bugs alone. A regular application will suppress whiteflies and spider mites, nasty nematode infestations, and fungus gnats. Butterflies, ladybugs, earthworms, and bees all remain unaffected.

The regular application of neem oil also helps suppress various other pathogens that could affect cannabis. Rose black spots, powdery mildew, rust, and other fungi endemic to humid conditions cannot take hold. Neem oil can also be useful to prevent or control root rot while working as a mild growth stimulant.

Neem oil acts as a prophylactic measure for pathogens and pests when applied every ten days. Prevention is the best practice. If there isn’t an active harm prevention policy in place, infestations can occur. In this instance, neem oil can also be used as a direct pesticide.

How to Use Neem Oil

As mentioned above, you will need to create a topical foliar spray to use neem oil. When you have mixed up your spray, simply apply it to the plants. It’s important to coat as much of the surface as possible.

For mites and other insects, it’s especially important to cover the underside of the leaf because that’s where they reside. It’s virtually impossible for them to attach an egg to the oily surface.

Here’s a step-by-step guide for using neem oil:

  1. Check your neem oil product for instructions on the correct percentage to use. Typically, the amount is very small: 0.1-0.2%. Be sure to read the label to get the exact amount.
  2. Mix the right amount of neem oil into your soapy water using a dropper.
  3. Add your soapy neem solution to a garden sprayer.
  4. Generously spray your plants from all sides – get the upper sides and undersides of the leaves. Spray just before the “dripping point,” but ensure that the entire plant is well-covered. Shake the bottle frequently when you spray to keep the solution well-mixed.

It’s also useful to spray the soil because some insects lay their eggs in the ground. Furthermore, the fatty acids in the oil are beneficial for the soil food web.

If you don’t see immediate results, don’t be discouraged. Remember, neem oil doesn’t work by direct contact. Instead, it disturbs the hormonal systems of the insects, meaning it may take some time.

You should apply neem oil to your grow regularly – once a week is an ideal schedule to prevent pests. However, if you have an active pest problem, you may wish to use neem oil every other day until the population is under control.

Importantly, you should avoid using neem oil three weeks before harvest because the lingering oil may affect the final flavor. That said, it would be very bad luck for something to go wrong in the last three weeks.

Final Thoughts on Neem Oil for Cannabis Growing

Finding an insecticide that is both non-toxic and effective can be challenging, but neem oil is exactly that. It’s a great way to protect your plants without having to resort to harmful and toxic chemicals.

When used regularly during all growth phases, neem oil plays an important part in maintaining plant health. It’s great for pest and pathogen prevention and is also a great topical solution if you have an infestation.

Neem oil is perfectly safe to use and can be harmlessly applied to cannabis plants, protecting them from fungi and insects. Basically, neem oil is an essential addition to any organic cannabis garden.

Plant Protection
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