All about neem oil

When someone starts gardening in the Gulf, one of the first things they will hear about is neem oil.

People that don’t come from Asia might have never heard about it, as neem oil is a natural pesticide that comes from the seeds of the Neem tree, which doesn’t grow in colder climates.

Neem tree origin and expansion

The Neem tree is native to north-eastern India and grows mostly in Asia and Australia. It also grows well in the Gulf region, as it’s extremely heat and drought tolerant.

Neem tree today has the botanical name Azadirachta indica and belongs to mahogany family, Meliaceae.

The name Azadirachta is derived from the Persian. Azad means “free”; dirakht means “tree”; i-Hind means “of Indian origin”. So the Latin name literally means “the free tree of India”.

Uses of neem oil

All parts of the neem tree – leaves, flowers, seeds, fruits, roots and bark – have been used in traditional medicine for the treatment of inflammation, infections, fever, skin diseases and dental disorders.

Due to its antimicrobial properties, neem oil can also be added to homemade cleaning products to help kill germs and bacteria.

In gardening, we use the oil that is extracted from the kernels to control pests in a natural way and even get some mild fungicidal benefits at the same time.  

How does neem oil act?

Neem oil works as a preventative method as well as pest control for an existing infestation of the most common insects that appear in our gardens in the Gulf:  

Leaf miners, Spider mites, Beetles, Aphids, Mealy bugs (in combination with rubbing alcohol)

 The precise mode of action of neem oil on certain insects hasn’t been clearly defined by research so far.  Different neem extracts have been found to act on different insects in various ways and the exact effects are often difficult to pinpoint.

But, despite all the uncertainty over details, various neem extracts are known to act on various insects in the following ways:

• Disrupting or inhibiting the development of eggs, larvae, or pupae;
• Blocking the molting of larvae or nymphs;
• Disrupting mating and sexual communication;
• Repelling larvae and adults;
• Deterring females from laying eggs;
• Sterilizing adults;
• Poisoning larvae and adults;
• Deterring feeding;
• Blocking the ability to “swallow” (that is, reducing the motility of the gut);
• Sending metamorphosis awry at various stages; and
• Inhibiting the formation of chitin. (source)

To read more details on how neem oil affects each order of insects, you can click here.

Neem oil can be used to control certain fungal diseases, such as powdery mildew, by preventing the growth and spread of fungal spores on plant leaves. While it cannot fully eliminate an existing fungal infection, it can help prevent the disease from spreading to healthy tissue.  

How to extract neem oil

There are many methods for extracting neem oil from the seeds of the neem tree. Here are the two most common ones:

Cold press method: To extract oil from neem seeds using this method, the seeds are ground into a paste and then pressed to release the oil. This process can be done at home with a manual or motorized oil press, but it is important to make sure the seeds are ground finely in order to get the maximum amount of oil.

Solvent extraction method: To extract oil from neem seeds using the solvent extraction method, a chemical solvent is used to dissolve the oil from the seeds. The seeds are ground into a powder and mixed with the solvent, and the mixture is then filtered to separate the oil from the solvent. While this method can produce a larger yield of oil compared to the cold press method, it is also more complex and involves the use of potentially dangerous chemicals.

The quality of the neem oil produced using these methods can vary. Cold-pressed neem oil is generally considered to be of higher quality, as it retains more of the natural compounds and nutrients found in the seeds. However, solvent-extracted neem oil may be less expensive and more widely available.

In general, to produce high-quality neem oil, it is important to start with fresh, good-quality neem seeds, no matter which extraction method is used.

Gardening application

Method of application: Spray with a mix of neem oil, liquid soap and water.

Solution preparation:  

Add 1 teaspoon of neem oil and a few drops of dishwashing liquid in 1 liter of water, mix well and spray.

Make sure you spray well the top and bottom of the leaves, as most insects prefer to live under the leaves.  

Repeat every 5 days, at least 3 times and monitor the insects’ population.

For preventative applications, spray every 10 days and check your plants closely on top and under the leaves.

Timing: As mentioned above, neem oil can kill insects during different stages of their lifecycle (eggs, larvae, pupas, and adults) and it is non-toxic for humans, so it can be used at any time during the growing season. However, make sure to wash well with soap and water any vegetables that have been sprayed with neem oil before they are consumed.

The only period to avoid the use of neem oil (unless it’s absolutely necessary) is when the temperatures are above 45 C, as it can burn the leaves.

Spray with neem oil during the morning or evening hours. Avoid using neem oil during the middle of the day, as the combination of neem oil and direct sunlight can burn the plants.

It’s important to note that neem oil is generally considered to be a safe and natural pest control option, as it is not toxic to humans or most beneficial insects. However, it is still important to follow the instructions on the product label and use it in moderation to avoid any negative effects on plants, beneficial insects and humans.

Neem oil alternatives – advice by the gardeners of the Gardening Club Qatar Facebook Group

If there is neem oil shortage in the market, here are some homemade alternatives that can support your garden until you can get some actual neem oil.

Note: this advice can be found in our online community; however, it hasn’t been tested by Hadiqaa Middle-East

• Sprinkling neem powder on the infected plants: Can be made at home by drying neem leaves and crushing them.
• A handful of fresh neem leaves can be finely chopped and left in 1 lt of water for 3 days to ferment. Then dilute part of this mix with more water and dish soap and spray.
• Boil fresh neem leaves for about 15 mins along with one small fresh turmeric rhizome. Keep the solution covered for 24 hours. To use it, dilute this solution in 1:5 ratio with water and spray.
• Boil a handful of neem leaves in 1 liter of water till the leaves color fades. Cool and strain the mixture, then add a few drops of liquid soap and spray your plants.
• Boil 2 to 3 handful of neem leaves in 1 cup coconut oil for 30 minutes at low flame. Cool and strain the mixture, then add a few drops of liquid soap and spray your plants. Store in a bottle.
• As mulch: Dry, crush and add neem leaves on your houseplants as mulch.

Resources

• Gardening Club – Qatar (Facebook group)
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3695574/
• https://pubmed.ncbi.nlm.nih.gov/15777222/
• https://extension.unh.edu/blog/2020/01/what-should-neem-be-used-plants#:~:text=Neem%20oil%20can%20be%20used,continue%20to%20feed%20and%20reproduce.
• https://www.ncbi.nlm.nih.gov/books/NBK234642/