Neem oil is an extract of Azadirachta indica, which has some interesting characteristics. The oil serves as an effective insecticide with both antibacterial and anti-fungal properties.
The primary active chemical, Azadirachtin, is often extracted for use as an active ingredient in chemical pesticides. Commercially, you can buy premade neem sprays, but these often include additional chemicals, and you have less control over the ratios.
Thankfully, it’s easy to make your own neem oil foliar sprays using just a few ingredients.
How To Make Neem Oil Spray For Plants
Once you understand the basics, making a foliar spray that doubles as a leaf shine and natural pesticide are quick and painless.
Here’s everything you need to know on how to make a basic neem oil spray.
Choosing The Right Concentration
At first, glance, pitching your neem oil can seem confusing.
There are two main types, 100% percent raw neem oils and clarified hydrophobic neem oil.
For foliar sprays, you’ll always want to get the clarified Neem, as this has most of the Azadirachtin removed, making it less harsh to the plant’s surface.
When the information’s available, you should also always buy neem oil that’s been cold-pressed, as neem loses effectiveness when exposed to heat.
You will also find that clarified neem comes in concentrations ranging from .5 to 3% percent.
This is the amount of Azadirachtin still in the oil, and you can usually use the lowest percentage for most applications.
When dealing with an infestation that .5% percent neem is failing to control, you can increase the concentration by increments.
Remember, the higher the percentage of Azadirachtin, the more likely it is to cause chemical burns to sensitive plants when directly applied.
Related: How Often Can You Apply Neem Oil?
Because oil and water don’t mix, you’ll need to make some emulsified water.
Emulsified water is simply water where soap has been added to break the surface tension.
There are three popular types of soap used in neem sprays:
- Dawn dish liquid is the most popular, as it’s non-toxic when diluted and safe for use around both plants and animals.
- Insecticidal soap can be used for an extra kick when dealing with an infestation, but be warned it can leave behind residue.
- Pure castile soap is an extremely useful, non-toxic form of soap used in many cleaning products.
Regardless of the type of soap you use, you will need to mix it in at a ratio of ⅓ to 1 teaspoon per quart, or 1 to 2 teaspoons per gallon (the exact amount isn’t important as long as it fits within these ranges).
Stir gently to blend the soap without causing it to froth.
Making the Spray
To make a spray, simply stir in 1 teaspoon of your clarified neem oil per quart (or 1 tablespoon per gallon).
Pour the mixture into a spray bottle for a simple, effective spray.
However, you can add additional ingredients to this basic spray as well.
Essential oils work great as a repellent and may also kill some pests on contact.
Additionally, many experts recommend either ⅛ or ¼ teaspoon of aloe vera powder to your neem spray, as it can help boost the plant’s immune system.
Be warned, any sprays made with aloe powder must be used immediately, as it spoils fairly quickly.
Related: Using Neem Oil For Tomato Blight
Neem Application Tips
There are a few basic rules you should always follow when using a neem foliar spray.
First and foremost, ALWAYS test a small part of the plant one day before spraying, as plants can develop allergies and have skin sensitivities just like people.
Second, be aware that spraying neem outdoors must be done at dawn or dusk, as it can harm honeybees or other beneficial insects if they come in direct contact with the neem oil.
Normally, the neem evaporates in 45 minutes to an hour without leaving behind any residue, but adding other ingredients such as essential oils or using insecticidal soap may cause neem residue or a slower dissipation rate.
Third, be aware that the intensity of the application differs based on your intent.
Using neem as a leaf shine can be done by spraying a soft cloth or paper towel and wiping down the leaves.
When using as an insecticide, however, you will need to spray every part of the plant liberally, including the undersides of leaves, stems, joints, and crevasses.
The only part of the plant you should avoid spraying is the flowers if treating an outdoor plant.
The foliar spray will kill most pests on direct contact but won’t destroy the eggs.
Be aware that it takes 14 days of applying every other day for the neem to begin visibly reducing an infestation.
You can also apply the foliar spray as you would in an infestation every three weeks to help prevent new bug issues from starting.