The Neem has adapted to a wide range of climates. It thrives well in hot weather, where the maximum shade temperature is as high as 49° C and tolerates cold upto 0° C on altitudes upto 1500 m.
Today, the Neem is well established in at least 30 countries world-wide, in Asia, Africa and Central and South America. Some small scale plantations are also reportedly successful in the United States of America.
The Neem grows on almost all types of soils including clayey, saline and alkaline soils, with pH upto 8.5, but does well on black cotton soil and deep, well-drained soil with good sub-soil water. Unlike most other multipurpose tree species, it thrives well on dry, stony, shallow soils and even on soils having hard calcareous or clay pan, at a shallow depth. The tree improves the soil fertility and water-holding capacity as it has a unique property of calcium mining, which changes the acidic soils into neutral.
Neem tree needs little water and plenty of sunlight. The tree grows naturally in areas where the rainfall is in the range of 450 to 1200 mm. However, it has been introduced successfully even in areas where the rainfall is as low as 200 – 250 mm. It cannot withstand water-logged areas and poorly drained soils.
The Neem grows slowly during the first year of planting. Young neem plants cannot tolerate intensive shade, frost or excessive cold.
A Neem tree normally begins to bear fruit between 3 and 5 years and becomes fully productive in 10 years. A mature tree produce 30 – 50 kg. fruit every year.
It is estimated that a Neem tree has a productive life span of 150 – 200 years.
The neem tree is native to tropical South-East Asia where it is recognized as an important medicinal plant. As it grows quickly and is extremely drought resistant, it has been cultivated for a long time in the arid zones of Asia, Africa and Central America as a source of timber. In India and Sri Lanka, its seeds and leaves are used for store pest control and oil is extracted from the seeds for the production of soap. Both the cold pressed neem oil and the oil-free part of the seed kernel can be used for pest control. The leaves of the neem tree also contain insecticidal and repellent substances although in much lower concentrations.
The seeds should be as fresh as possible as older seeds often do not germinate. Provided that only a few trees are to be planted, and there is sufficient moisture available, with minimum weeds, the seeds may be sown directly into the ground. Two to three seeds are placed together about 1 cm deep in loose soil. After germination, only the strongest plant should be retained. When planting a large number, it is advisable to cultivate young plants first in pots, trays or plastic bags. After 3 months, they should be transplanted into the ground. When using bags or pots care should be taken that the plants are not allowed to develop to a stage where the tap root has pierced the bottom and has to be shortened before transplantation. This weakens the trees and substantially slows their growth.
Neem trees bloom for the first time when they have reached the age of 2 to 3 years, and bear fruit at the age of 3 to 4 years. They normally produce fruit once a year, but in some moist zones twice a year. The fruit of the neem can either be shaken off the tree, picked, or stripped from the branches. When ripe it is yellow in colour, about 2 cm in length and oval-shaped. In the soft, sweet fruit there is a light-coloured seed of about 1.5 cm in length, containing one, or sometimes two, brown seed kernels. After harvesting the fruit the ripe pulp should be removed as quickly as possible. In some regions, birds or fruit bats eat the sweet pulp, so that a lot of clean seeds can be found on the ground.
In order to dry the seeds, they are spread out for a few days on a solid and dry ground in the sun. The layer of seeds should be as thin as possible, as when drying grain, legumes, coffee or cocoa beans. The drying process must be carried out very carefully as undried seeds can become mouldy quickly. During the rainy season the seeds to be dried should be promptly covered over or brought indoors before rain showers begin.
As the dried sees can also become mouldy during storage, they should only be stored in airy containers (e.g. jute sacks or baskets). Airtight containers such as plastic bags or pots are unsuitable.
To produce a spraying mixture with 10 ltrs of water, 500 gms neem seeds are required. If it is not possible to weigh the seeds, containers, such as traditional measuring tins and pots etc., where the capacity is known, are equally suitable for measuring the correct amount of seeds and water.
Before mixing, the seeds are crushed or pounded preferably in a mill or mortar, then the crushed seeds are poured into the water and stirred vigorously.
This mixture should now be left to stand for atleast 5 hours – if possible overnight – in order that the neem substances are fully released from the seeds into the water solution.
Neem extracts are particularly suitable for use on vegetables and small scale field crops. If sufficient water and sprayers are available it is also possible to treat larger fields.
Numerous insect species are repelled by active ingredients in the neem seed. As they find the taste and smell unpleasant they avoid the plants that have been treated with neem extracts. Other insects die some time after having eaten leaves or other parts of the plant treated with these substances. They alter the behaviour in some insects or reduce their ability to lay eggs. Other pest species are affected minimally or not at all by the neem substances, probably as a result of their hidden biology.
The neem extract can be applied in two ways: When using a sprayer, the rough particles must first be filtered out of the mixture to prevent clogging the nozzle. This is done by covering a bucket or similar container with a coarse cloth or gauze through which the mixture is poured. The sprayer is filled with the filtered solution and spraying of the vegetable crops can begin.
If no sprayer is available the extract may be applied with a straw brush. In this case, it need not be filtered. A brush made with fine, flexible straw is simply dipped into the solution and shaken over the plants until all the leaves are moistened. The effect of the neem substance lasts between 3 to 6 days, regardless of how it was applied.
If and when spraying is necessary depends very much on the individual case and this can only be decided by the farmers or the appointed adviser. In general, it may be said that in areas of vegetable cultivation, where pests are a great problem, weekly spraying is necessary. If, on the other hand, infestation is only slight, treatments in intervals of 10 to 14 days are adequate. Often a single treatment of the plants is sufficient. Just as with chemical insecticides, the insect species and crop are important factors in deciding how often spraying should occur. According to scientific research the extract is not poisonous for humans, thus, it is not necessary to wait long between final spraying and harvesting.
The neem extract does not have the same effect on all insect species. Some pest groups can be easily controlled. The feeding behaviour of other groups may be influenced or their ability to reproduce impaired, but this does not prevent direct damage to the plants. Some insects react minimally or not at all to the extracts.
Given below you will find more detailed information on the reactions of pests of neem extracts. It is important to note, however, that this is not intended as a precise description of the effects of neem extracts but as a guide which gives the user advice as to which pests may be controlled by application of neem.
Stem borers on young corn and sorghum plants can be controlled relatively easily with crushed neem seeds (the powder normally used to mix with water). A small amount of powder mixed with sawdust or dry clay at a ration of 1:1 is placed in the funnel. 1 kg powder should be sufficient for 1500 – 2000 plants.
In this method, rainwater dissolves the substances in the neem seeds as it gathers in the funnel and washes out the powder. Where rainfall is irregular a liquid neem seed extract can be sprayed into the funnel.
This treatment should be repeated every 8 to 10 days during the sensitive growing phase. Thus, roughly three treatments are sufficient for protection against stem borers. This recommendation applies only for young plants before flowering and not for older plants.
Stored grain legumes can easily be infested with bruchids. These are small beetles whose larvae eat into the grain. The bruchids can be controlled simply by mixing the legumes with neem oil.
Neem oil is extracted from the neem seed kernels (oil content 40 – 50%). When used for storage protection it should be carefully pressed, either by machine or various other traditional methods. As only a very small amount of oil (30 ml oil per 100 kg grain) is required, pressing by hand is practicable. The seeds must first be shelled, by cracking the shells with a stone or gently pounding in a mortar and finally by winnowing to remove the shell particles.
If the crushed seeds are very hard and brittle they should be moistened and left to stand for several hours until they can be pressed together by hand. Crushing the seeds in a mill or mortar produces a rough, sticky mixture out of which can be pressed by kneading. Usually it is necessary to add a little water to make kneading easier.
By alternating kneading and pressing of the paste in a bowl the neem oil is released. Using this method it is possible to extract 150 ml oil from 1 kg powder. The legume seeds are treated with neem oil extracted in the following manner: The appropriate amount of neem oil is mixed with the legume seeds in a large bowl or similar container (3 ml per 1 kg grain); then the seeds may be stored in the usual way.
Neem oil is non-poisonous but very bitter, thus freshly treated legumes taste at first very sharp. This taste disappears, however, after 3 to 4 weeks.
Apart from its previously described application for storage protection, neem oil has been a trusted remedy for a naturally healthy skin in the villages of India. Derived from the seeds of the neem tree it contains all the disinfecting and healing properties of the tree, in a concentrated easily usable form. For centuries, this therapeutic oil has provided protection and
Scientific studies have shown that Neem contains certain chemicals, which are unique. The primary chemicals are a mixture of 3-4 related compounds called limonoids. Neem seeds also contain a few chemicals that have sulphur. These phyto-chemicals add the characteristic smell to the neem oil. They also attach additional curative properties to the oil. It has a dark yellow color, turns solid at temperatures below twenty-three degrees Celsius, and does not dry out. The oil is composed mainly of glycerides of palmitin, stearin, oil and linol acids. It chemically resembles soy oil or olive oil. In the cold-pressed oil, there are also 10 to 20 percent of the total content of biologically active components, especially the limonoids. Bitter components contained in neem oil and certain sulfur compounds that give the oil its strong garlic scent, destroy the taste.
It is a completely natural total first aid tool for families. Due to its unique composition it has an almost magical effect on chronic skin conditions that fail to respond to conventional treatments. What makes neem oil outstanding in comparison to other remedies is that it is active against all three varieties of infectious organisms: Bacteria, Fungii and Viruses. The oil is known to provide a very effective germicidal action. Modern science has now confirmed the effectiveness of Neem oil in fighting infection. Scientific studies indicate that Neem has very powerful skin rejuvenating qualities and it is being hailed as the Oil of Wonder.
Many strains of bacteria are found to be resistant to the modern antibiotics. Neem oil has a seemingly endless range of antibacterial uses. This has prompted the development of neem as an anti-bacterial drug for these resistant strains, against which it has shown promising activity in the laboratory tests. Because of its antiseptic qualities, neem oil is also well suited for medicinal soaps and pharmaceuticals such as salves and creams. Neem oil is used in cosmetics for creams, lotions and shampoos.
It has a wide spectrum of action and can be safely used for a variety of skin conditions. Neem oil and many of its constituents have been successfully used against a wide range of bacteria, viruses, fungi and parasites. Neem oil has been reported to be effective against certain human fungi, which are even difficult to control, by modern synthetic fungicides. These include some Trichophyton, Epidermophyton, Microsporum, Trichosporon, Geotricum and Candida. Neem oil inhibited the growth of all the three strains of Mycobacterium in a concentration of 12.5 mg/ml.
Neem oil has consistently shown moderate to potent anti-bacterial activity against a wide range of Gram positive and Gram negative microorganism. The oil possess marked spectrum of anti-bacterial activity against Gram negative and positive microorganisms including M. tuberculosis, streptomycin resistant strain. Neem oil absorbs quickly into the skin and has good skin penetration. It’s compounds are non-irritating and are known to have a minimum of allergic reactions. It is neither too hot (ushna) nor too cold (sheetha) in potency (veerya) and subsides pitta and kapha dosha, promoting holistic health for mind, body and spirit.
If you are looking for a natural remedy for skin irritations, pure medicinal grade Neem oil could well be your answer.
Apart from its suitability to provide shade and for Afforestation the wood of the neem tree is very much in demand. The trunk and branches are ideal for building being both strong and rather resistant to termites. It is also used for firewood and in the making of charcoal.
There is an important point to remember when using neem for firewood: If, as is common practice in many countries, the branches and the top of the tree are regularly pruned, it will be some time before the trees again produce fruit as they will first try to re-establish branches. Thus the combined use of the neem tree for insecticide and firewood is only possible when the tree is left undisturbed for several years. In other words: In order to produce insecticide, the original branches should be left intact (fruit production begins in 3 – 4 years). Only trees that are at least 10 years old should be used for firewood and only after the younger trees, planted later, have begun to produce sufficient fruit.
The neem tree (Azadirachta indica A. Juss) thrives almost anywhere in the tropical lowland, upto 800 m above sea level. It is resistant to extreme drought and grows where the annual rainfall is as sparse as 300 mm. Moreover, it grows very quickly and makes few demands on the soil fertility. The neem tree, therefore, grows in a wide variety of places. Hilltops and infertile, depleted land (e.g., Eroded hillsides) are as suitable as stony, flat land or hard laterite. The neem tree may be used to line avenues, to border roads or fields and in mixed cultivation with fruit trees. The average annual fruit yield from a mature neem tree is above 20 kg. Apart from insecticides, neem oil may be extracted from the seed. 30 kg neem seeds produce 6 – 8 kg oil. The resulting residue can be used to make insecticides in a similar way as from the whole neem seeds described earlier.
All parts of the neem tree can be utilized. Insecticidal substances are present in various parts of the tree; the highest concentrations are, however, contained in the seeds.
Azadirachtin, the most important insecticidal substance contained the plant, has, even in very small doses, a growth disrupting effect on many insect larvae, i.e. insects which eat this substance are unable to develop to the next larval / nymphal stage and die off. Other pests, such as grasshoppers, avoid or reduce feeding as a reaction to azadirachtin. As tests have repeatedly confirmed, due to its special mode of action, the neem extract is quite harmless for useful insects. Unlike synthetic pesticides, tests carried out over a longer period indicate that development of any resistance to the neem extract is in the short term unprobable. However, where intensive vegetable cultivation is practiced, the exclusive use of neem extract is inadvisable.
One great advantage of the neem extract is that even after repeated application on vegetable crops, it remains perfectly harmless for humans.