Cotton

• It can be grown from sea level to an elevation of 1200-1500 m but low temperature at higher elevation limits cotton production.
• Cotton is a warm season/heat loving crop and there is a linear relation between heat unit and cotton yield. It requires a mean annual temperature of 160C & an annual rainfall of at least 50 cm distributed throughout growing season.
• A daily minimum temperature of 160C is required for germination (320C being optimum) and 21 to 270 C for proper vegetative growth and can tolerate up to 430C but does not perform well if temperature falls below 210C and below 150C it makes hardly any growth.
• The optimum night temperature requirement is 15-200C. During fruiting phase, day temperature ranging from 27-320C and cool nights are favorable.
• Cotton is a short-day plant but upland cotton is a day neutral. It is sun loving plant and cannot tolerate shade, particularly in the seedling stage.
• Cotton is drought resistant plant due to its well-developed root system i.e. tap root with secondary roots that branched laterally from primary root. It absorbs moisture from sub soil layer and can withstand short period drought.