Neem oil is generally considered one of the safest, most useful natural insecticides on the market. In its purest form, it is literally the oils extracted from cold-pressing various parts of Azadirachta indica, especially the seeds.
Pure Neem oil contains several active compounds, the most important of which is Azadirachtin. Azadirachtin interferes with an insect’s reproduction, growth, and appetite.
But what makes neem oil especially useful is that the substance is non-toxic to both humans and pets, and most plants can be treated with neem safely.
However, neem oil cannot be applied directly, so it’s important to know how to properly mix and apply it.
How To Use And Mix Neem Oil For Plants
There are different types of neem oil, as well as numerous possible recipes.
The following are some basic go-to recipes, as well as some suggestions for more complicated mixes.
Making an Emulsion
Neem oil on its own is too strong for most plants and can severely burn them if not diluted.
Regular water won’t be able to mix with oil, so you’ll need to make an emulsion.
Emulsified water is merely a mix of water and a small amount of soap.
Soap breaks the surface tension of water, allowing oil and other substances to be blended in.
To make an emulsion, you will need to gently stir in approximately ⅓ teaspoon of soap per quart of water, or one teaspoon per gallon.
Dawn dish soap is a popular choice due to its gentle nature, but you may also use pure castile soap or insecticidal soap for maximum effect.
Testing your Plants
Always test a small portion of your plant a day before treating it with neem or any other substance.
Plants, like people, can develop sensitivities or allergies to products.
As a result, you might have one spider plant that loves neem and another in the same room that suffers contact burns.
100% Percent Raw Neem Oil (Soil Soak)
Pure neem oil is very potent, and should only be applied as a soil soak.
The soak contains 2 tablespoons of 100% percent cold-pressed neem oil per gallon of emulsified water.
It’s important to get only cold-pressed, as the application of heat reduces neem’s potency.
The soak is poured directly on the soil around your plant, usually 2 to 3 cups at a time, although larger plants may require more.
Neem soil soaks attack fungus and ground-based pests without harming earthworms.
The roots absorb most of the neem, turning it into a systemic insecticide that lasts for up to 22 days and is consumed by any pest that breaks the plant’s surface.
It’s safe to use soil soaks every three weeks as a preventative, and food crops may be treated up to the day before harvest.
Clarified Neem (Foliar Sprays)
Clarified hydrophobic neem oil is the result of processing neem oil to remove the Azadirachtin for use in other products.
This version of neem is still quite useful and is commercially available in concentrations of .5 to 3% percent.
Under most circumstances, the .5% percent is enough for a foliar spray, but you may choose to get a stronger version as needed.
You will only need 4 teaspoons of clarified neem per gallon of emulsified water, poured into a spray bottle.
Unlike raw neem oil, clarified neem dissipates in 45 minutes to an hour, leaving behind no residue.
Note that insecticidal soaps or any other ingredients you add may leave behind their own residue or take longer to dissipate than the neem.
As neem can harm bees and other beneficial insects on contact, you should only use foliar sprays outdoors at dusk or dawn when bug activity is minimal.
Application of the foliar spray is more time-consuming than a soil soak, but it kills pests almost instantly.
You will need to completely coat your plant, paying special attention to the undersides of leaves and any joints or cracks that pests might try to take shelter in.
The foliar spray will need to be reapplied every other day for at least fourteen days during an active infestation.
Conversely, it may be applied once every two weeks as a preventative measure and leaf shine.
Neem Cakes (Fertilizer)
The solid waste left over from extracting raw neem is pressed into cakes and sold as a natural compost.
These cakes contain trace amounts of Azadirachtin and can be used as a plant food as well as a preventative treatment.
Using bits of neem cake has been known to help combat the fungi that cause root rot, as well as helping to protect against harmful grubs.
As different companies may sell cakes that have their own concentrations or extraction methods, you should always pay attention to the instructions on the label.
Improving on Foliar Sprays
While the neem foliar spray on its own can be beneficial, you can add a lot of different ingredients to make the effects last longer.
Some of the more popular additives are garlic or onion juice and cayenne pepper.
These substances repel all sorts of pests and will remain on the plant for a few days, even though the neem itself will vanish in an hour.
Try mixing in different herbs or spices that specifically target the noses of other pests such as rabbits or raccoons to get even more benefit from an outdoor foliar treatment.