If you garden, you probably have heard of neem oil for plants at some point. Neem is popular among organic gardeners, but it has remained a mysterious, almost mystical substance.
There are a lot of people who swear by neem and many who are wary of it. Ask someone about the natural products of neem oil often results in very little information.
So what is neem oil, where does it come from, and how is it used?
Here are the answers you’ve always wanted but could never find.
What Is Neem Oil and How Is It Used and Applied?
Neem oil is an entirely organic insecticide and fungicide that is non-toxic to humans and pets. More on Neem oil as a fungicide.
It has a long history of use and is becoming one of the go-to insect pests solutions for plant enthusiasts.
Where Does Neem Oil Come From?
Neem oil comes primarily from the seed extracts of the Azadirachta indica tree.
This plant, known as the Indian lilac or neem plant originated in the Indian subcontinent. It is now grown in over 70 countries as an ornamental and for use in pest control.
Its active pesticidal compound, Azadirachtin, can be found in all parts of the plant but is most concentrated in the seeds.
The seeds (and often fruit) are crushed to extract their natural oils, usually through a cold-press method to ensure no potency loss.
Any solids left over are used to make neem cakes, while the resulting oil is known as raw or crude neem oil.
Raw neem oil is available in many garden centers and online, but a large percentage is refined further to remove the Azadirachtin.
The resulting processed oil is known as clarified hydrophobic neem oil and sold in commercial foliar sprays.
What Is Neem Oil Used For?
Neem oil has a long tradition of use and has been a longstanding part of Ayurvedic medicine.
It is believed to provide many health benefits, including:
- Blood detox
- Digestive and respiratory aid
- Immune system booster
- Improved circulation
- Improved liver function
Over the centuries, its found use in numerous health and beauty products, such as candles, soaps, toothpaste, and cosmetics.
While sometimes used in cat and dog shampoos as an anti-flea medication, research has found cats especially may become sick and even die when treated with neem shampoos.
Overall, neem oil is considered safe and non-toxic for human consumption and is also deemed safe for use around cats and dogs, with the exception mentioned above.
But neem oil’s true claim to fame is what it can do for plants.
What Is Neem Oil Used For On Plants?
Azadirachtin is a toxin that closely resembles developmental hormones in many insects.
When ingested, an insect may lose the desire to eat, be unable to reach the next developmental stage, or fail to produce eggs.
Clarified hydrophobic neem oil still contains trace amounts of Azadirachtin. It can have the same effect as crude neem oil and easily clogs the airways of insects it comes in contact with, causing them to suffer and die.
Even neem cakes are beneficial, serving as organic compost with traces of Azadirachtin that can kill insects hiding beneath the soil.
Neem oil is known to kill more than 200 (and possibly as many as 600) different species of insects, including neem oil for aphids, mealybugs, plant scale, spider mites, caterpillars, and many more.
For details, check out our article: What Bugs Does Neem Oil Kill?
When rubbed on the skin, it repels mosquitoes and can kill them if ingested.
Neem oil will NOT harm earthworms, slugs, or snails and is garden safe for use around pollinators as long as any topical treatments are applied when bees and similarly beneficial insects are not active.
But Wait, There’s More About Neem!
Neem oil deserves an infomercial because the benefits keep on growing.
In your plants’ case, it’s also an effective fungicide and can help cure many bacterial infections on stems, plant leaves and roots.
Some of the bacterial and fungal conditions neem oil will treat include:
- Anthracnose disease
- Black Spot on Roses
- Fire blight
- Leaf spot (Bacterial and Fungal)
- Powdery Mildew
- Root Rot – Learn how Neem Oil helps root rot
- Sooty Mold
- Stem Rot
- Tip Blight
- Verticillium Wilt
These treatments often require a tree or plant to be in its dormant stage or may have other special instructions specific to the condition being treated.
How To Use Neem Oil
Apply neem oil as a soil drench (soak) or foliar spray.
In both cases, gently mix a tiny amount of Dawn dish soap, castile soap, or insecticidal soap into the water as an emulsifier before adding the oil to help it blend.
Soil soaks require 100% percent cold-pressed raw neem oil at a ratio of 2 tablespoons per gallon and is poured directly over the plant’s roots.
The plant will absorb the neem oil, turning the Azadirachtin into a systemic insecticide that will kill any pest that attempts to bite or pierce the plant’s surfaces and remain toxic for up to three weeks.
Foliar sprays use clarified hydrophobic neem oil, usually at a .5 to 2% percent concentration.
A simple spray consists of four teaspoons per gallon of emulsified water. Always follow the pesticide products label.
It can kill a wide range of bacterial and fungal infections and poisoning plant insect feeding pests on contact. Soak all surfaces of the plant thoroughly to be fully effective.
However, the neem oil in a spray will dissipate in 45 minutes to an hour with no residue, making the plant safe for beneficial insects and pollinators.
Always use the foliar spray around dusk or dawn to kill the target insects. Reapply every other day for two weeks to eliminate an infestation or infection.
Use the two methods separately or as a combo. Neem also makes an excellent preventative treatment when applied monthly as a drench or sprayed every two weeks.
Neem is an amazing plant. The products from this plant produce many safe, natural organic tools we can use in the garden and home. Check out our growing list of neem topics.