CASTOR OIL PLANT: A POSSIBLE NEW INDUSTRY. 
Castor Oil Plant: A Possible New Industry. 
By W. B. ALEXANDER, M.A.* 
1. Introduction—Castor oil is derived from the seed of the castor plant, 
Ricinus communis, L., which is believed to be a native of North Africa and India. 
Of this plant there are numerous varieties, which are sometimes regarded as dis- 
tinct species. 
The castor plant is cultivated as a crop in India, Java, Brazil, and the United 
States, and is grown as an ornamental garden shrub in most of the warmer 
“countries of the world. ‘It is also found as a wild or semi-wild plant in most 
warm countries, having probably escaped from cultivation. 
In the tropics it forms a small tree from 20 to 30 feet or more in height. In 
warm-temperate climates it is a shrub 8 to 12 feet high, whilst in localities where 
frost occurs it is a herbaceous perennial. Under cultivation in temperate climates 
it is treated as an annual. 
In India the leaves are used as fodder for cattle, and in Assam they are used 
for feeding the Eri silkworm. The chief product of the plant is, however, the seed 
or castor-bean from which oil is extracted. 
The beans produced by different varieties vary in size, colour, and shape, as 
Well as in oil content. For practical purposes the varieties may be grouped as 
large- and small-seeded forms. The former are more prolific in yield, and the oil 
obtained from them is used chiefly for lubricating and industrial purposes; the 
small-seeded varieties yield the better quality oil used in medicine. 
2. Cultivation.—Since the castor plant is sensitive to frost it requires a warm 
climate or a temperate climate with a long summer. In general it will succeed 
in any locality where maize will ripen. Moisture is essential for the germination 
of the seed, but when once the plant is established it requires little rain, and 
excessive rainfall is injurious to it. The most suitable soils are rich, well-drained 
sandy or clayey loams, or in general soils which will produce good wheat or maize 
crops, Very loose sand and heavy clays are alike unsuitable. 
Deep ploughing and harrowing are essential. ‘The plant is exhausting to the 
soil, and, except in virgin land, requires manuring. Tor this purpose the residual 
cake left after expressing the oil is valuable, and the leaves and seed-husks of 
the plants are also useful if ploughed in. Pure crops should not be taken from 
the same land more than once in five or six years. In India it is not often grown 
as a pure crop, but is usually grown as a hedge round cotton or sugar fields: 
3. Harvesting—The capsules of the small-seeded varieties begin to ripen in 
four to five months; those of the large-seeded varieties in seyen to ten months 
after sowing. Since when ripe the capsules of many varieties burst suddenly and 
scatter the seed to a considerable distance, it is necessary to gather the spikes 
bearing the capsules as soon as they show signs of ripening. When ripening has 
commenced the crop requires looking over once a week, in order that ripening 
capsules may be gathered. An attempt has been made in the United States to 
produce a variety which ripens all its capsules at once, but, apparently, this has 
not been accomplished. 
The capsules when gathered are spread out on a floor, preferably in an open 
shed, where they are exposed to the sun and protected from the rain. They need . 
to be turned over from time to time. When all the capsules have shed their seed 
* Secretary to the Special Committee on the Castor Oil Plant, 
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