By Steven Voser

Heard about the benefits of insecticidal soap and neem oil? Wondering which one to choose to protect your cannabis plants from pests? Well, what if we told you that there was no need to choose one over the other? Keep reading to learn all about insecticidal soap and neem oil, and how they both work to stave off cannabis pests.

Insecticidal Soap: What Is It and How Does It Work?

Insecticidal soap is soap made using soap salts—or potassium salts of fatty acids, more specifically. It is an old-school approach to dealing with garden pests that's regaining popularity as gardeners look to more environmentally friendly ways to control cannabis pests and plagues.

Insecticidal soap is best applied as a foliar spray[1], and can be used both to deter pests from making a home in your garden[2] and to combat an active pest infestation. The soap works in three distinct ways:

  • By drying out insects: Insecticidal soap can penetrate some insects, damaging their cells and drying them out.
  • By suffocation: Insecticidal soap can suffocate some insects, such as aphids, by blocking their trachea.
  • By destroying eggs and larvae.

What Is Neem Oil and How Does It Work?

Neem oil is made by pressing the fruit and seeds of the neem tree (Azadirachta indica), which is native to Southeast Asia and India (where it is regarded as a holy tree). The resulting oil is rich in triglycerides and triterpenoids, and makes for an extremely effective pest control agent[3]. Unlike insecticidal soap, neem oil doesn't directly kill or damage insects[4].

Insecticidal Soap vs Neem Oil: Which Is Better?

Insecticidal soap and neem oil are both very effective natural pest/insecticides[5]. Neither is harmful or toxic to humans or pets (at least not in the doses used in pest control), and both are popular among growers looking for organic or natural alternatives to harsh chemical pesticides.

However, there are a few key differences between neem oil and insecticidal soap that may impact whether you choose to use one over another, including:

💰 Cost and accessibility: Neem oil is more expensive than insecticidal soap and harder to come by.

🐛 Efficacy: Neem oil is effective against a wider variety of garden pests than insecticidal soap (which only works against soft-shell insect pests). Neem oil also has antifungal properties, which insecticidal soap doesn't.

⚠️ Mechanism of action: Insecticidal soap is a contact killer, meaning it kills insects that come into direct contact with it. Neem oil, on the other hand, is a systemic pesticide; it is absorbed by plants once applied and only affects insects once they feed off the treated plant. This means that insecticidal soap might be faster-acting when used to combat a pest infestation, while neem oil can also be used as a repellent to keep pests away from your plants.

♻️ Environmental impact: Insecticidal soap easily breaks down in the environment[6], but is a non-selective pesticide (meaning it may kill insects that are beneficial for your garden). Neem oil, on the other hand, doesn't break down easily, but is selective, meaning it won't affect most beneficial insects living in your garden.

🥀 Plant risk: Both insecticidal soap and neem oil can burn plants[7] if used too often or in too-high concentrations. Neem oil, however, is a little harsher on plants than insecticidal soap.

Insecticidal Soap and Neem Oil

Can You Use Insecticidal Soap and Neem Oil Together?

While both insecticidal soap and neem oil work great on their own, they are far more effective when used together[8]—especially if you're actively fighting a pest infestation. The insecticidal soap will kill the pests on contact, while the neem oil will help to prevent the pests from coming back.

Here's how to combine insecticidal soap and neem oil for the ultimate protection against cannabis pests:

1. Mix 10ml of insecticidal soap into 1l of unchlorinated water. Stir or shake the mixture to ensure the soap and water mix well.

Step 1

2. Add in 3–5ml of neem oil. Shake very well to combine all ingredients.

Step 2

3. Use a pump spray bottle to douse your plants in the mixture.

Step 3

For the best results, treat your plants with insecticidal soap and neem oil once a week to prevent pests. If you already have an infestation on your hands, spray your plants 3 times daily for 3–7 days until the pests disappear, then spray once per week to keep them from coming back.

Can You Use Insecticidal Soap and Neem Oil on Flowering Cannabis Plants?

No. While insecticidal soap and neem oil are non-toxic to humans, we do not recommend using them on flowering cannabis plants, as you would not want to combust and inhale the residue of either. Plus, neem oil has a strong, fairly unpleasant odour that may negatively impact the aroma of your buds.

Insecticidal Soap and Neem Oil: The Perfect Team?

Neem oil and insecticidal soap are two pesticides/insecticides that offer a natural alternative to harsh chemical products. While insecticidal soap and neem oil have different mechanisms of action and different pros and cons, we recommend combining the two as part of your pest control measures for maximum protection. Just be sure to avoid spraying your buds, and keep an eye on how your weed plants respond to the treatment.

This content is for educational purposes only. The information provided is derived from research gathered from external sources.

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