This section gives an overview of the castor crop and provides information on the castor crop cultivation and the harvesting methods.

Castor Plant Overview

Plant History:

The castor plant has been known to man for ages. Castor beans have been found in ancient Egyptian tombs dating back to 4000 B.C., and the oil was used thousands of years ago in wick lamps for lighting. To many people the castor plant is just an overgrown, undesirable weed and yet it produces one of nature's finest natural oils.

Plant Description:

• The castor plant is a coarse perennial, about 10 ft tall in the tropics, with the stem 7.5–15 cm in diameter.
• Though it is a perennial, it usually behaves as an annual in the temperate regions. Its stems are succulent, and the plant is herbaceous.
• Its leaves are alternate, orbicular, and palmately compound, with 6–11 toothed lobes.
• Its flowers are numerous in long inflorescences, with male flowers at the base and female flowers at the tips. Petals are absent in both sexes, sepals number 3–5.
• Its stamens are numerous, 5–10 mm long. Its ovary is superior, 3-celled with a short style and 3 stigmas.
• The castor plant’s fruit is a globose capsule with a diameter of 2.5 cm, on an elongated pedicel, spiny, green that turns to brown on ripening.
• The fruit usually contains 3 seeds.
• The seeds are ovoid, tick-like and shiny. They are 0.5–1.5 cm long, carunculate, vari-color with base color white, gray, brownish, yellow, brown, red, or black. The outer patterns on the fruit are gray or brown to black, the pattern varying from fine to coarse, and in shape the outer patterns vary from veined or finely dotted to large splotches.

Plant Ecology:

Ranging from Cool Temperate Moist to Wet through Tropical Desert to Wet Forest Life Zones, castor bean is reported to tolerate annual precipitation of 2.0 to 42.9 dm (mean of 68 cases = 12.7) annual temperature of 7.0 to 27.8°C (mean of 68 cases = 20.4) and pH of 4.5 to 8.3 (mean of 29 cases = 6.5).

Grows best where temperatures are rather high throughout the season, but seed may fail to set if it is above 38°C for an extended period.

Plant requires 140–180 day growing season and is readily killed by frost. Irrigated crops require 2–3.5 acre-feet of water to produce satisfactory yields. High humidity contributes to the development of diseases.

Plants do best on fertile, well-drained soils which are neither alkaline nor saline; sandy and clay loam being best.

The varieties of castor recommended for different states of India are: 

 * Castor hybrid recommended for cultivation in Tamil Nadu is TMVCH by Oilseeds Research Station of the Tamil Nadu Agricultural University (TNAU), Tindivanam. This hybrid matures in 160-170 days. The seeds contain 51.7% oil. It is moderately susceptible to semilooper pest and moderately resistant to wilt and grey mould.

Source: Indian Agricultural Research Institute, 2008.

Major Germplasm Collections of  Castor (Ricinus communis L.) As Listed by the Bioversity International Directory (October 14. 2008) 

Source: National Agriculture Library, United States Department of Agriculture