Neem and its oil extract have been used in organic farming for many years.

What is Neem?

Neem (azadirachta indica) is an evergreen tree indigenous to the Indian subcontinent. Also called Indian lilac, it is a fast growing tree, often growing over 15 metres (50 feet) in height. It has dark green leaves and fragrant white flowers, which are often cooked as a vegetable dish in India.

Uses in Organic Farming

Neem different parts of the neem tree can be used in organic farming as a natural alternative to synthetic pesticides. The most common use is through an oil extract from the crushed seeds of the neem fruit. The oil is typically a red colour, and has a strong odour.

The spent hulls of the neem seed are also pressed into a cake and used as an organic fertilizer.

Neem oil, its extract and derivatives are approved for use in organic farming by OMRI (Organic Materials Review Institute).

How to Use It

Neem oil is typically purchased in liquid form, in regular strength or as a concentrate.  It is typically mixed with water and insecticidal soap and sprayed directly onto the plant foliage or areas where insects, fungus, and diseases are present. This solution can also be applied to the soil around the root area of the plant as well. We use the following in many of our gardens:

  • 5ml of neem oil concentrate or 10ml or neem oil
  • 1-2ml insecticidal soap (you can use liquid dish as an alternative)
  • 1 litre warm water
Mix the insecticidal soap with the warm water. While stirring the liquid, gradually add the neem oil to the solution. Transfer the mixture to a spray bottle. Shake the mixture while spraying to ensure even distribution of the neem oil. We recommend spraying plants in the morning, 2-3x per week over a two week period.

How it Works

Neem oil has a number of complex and active ingredients. These chemicals, such as palmitic acid and stearic acid, block the natural hormones insects produce which causes them to stop eating, mating or laying eggs, which in turn causes them to starve and eventually die. However, for this to be effective, neem oil has to be applied regularly over a minimum 2 week period.

Insects Affected by Neem

Neem oil has been used to repel a wide range of insects including aphids, cabbage worms, thrips, white flies, mites, fungus gnats, beetles, leafminers, nematodes, and Japanese beetles. Neem oil does not hurt beneficial insects. Only chewing and sucking insects are affected.

Urban Farming Applications

For urban farmers dealing with outbreaks of different pests, neem oil can be an effective natural pesticide and insecticide.  Unlike other pesticides which poison both plants and insects, neem oil does not have any negative affects on plants. For best results, neem oil must be applied 2-3x per week over a minimum two week period. It does not have an instant effect, but does produce long term benefits.

Other Notes

Neem oil can also be used to control powdery mildew and rust.  It can also be used as a natural product to boost the shine on plant leaves, especially for indoor plants.

Where to Buy Neem Oil

Neem oil can be found at many garden centres. It can also be purchased as a concentrate directly from Young Urban Farmers at our online store.

neem tree large flickr

Cover Image by Anand Nav, used under its Creative Commons license.