Cotton

Overview

Upland cotton (Gossypium hirsutum) is a perennial shrub in the mallow family (Malvaceae) that is typically cultivated as an annual crop. Native to Central America, Mexico, and the Caribbean, it has become the dominant cotton species in global agriculture due to its adaptability, yield, and fiber quality. The plant typically grows 1-2 meters tall in cultivation, though wild forms and certain varieties can reach 3 meters or more. The species is characterized by its distinctive lobed leaves, showy cream to yellow flowers with purple or red spots at the base of each petal, and most notably, its seed-bearing bolls that split open at maturity to reveal masses of white or cream-colored fiber attached to seeds. These fibers, which are single-celled trichomes that develop from the seed coat, are harvested for textile production and are the primary economic product of the plant. Cultivated cotton requires warm temperatures, a long growing season (typically 180-200 days), and moderate to high water availability during growth stages. Modern cotton agriculture employs intensive management practices including irrigation, fertilization, and pest control. The species has undergone extensive breeding and genetic improvement, with thousands of cultivars developed for specific growing conditions, fiber qualities, and resistance to pests and diseases. Beyond its fiber, cottonseed is processed for oil used in cooking and industrial applications, while the remaining seed meal serves as livestock feed. The plant's global economic importance is immense, supporting livelihoods for millions of farmers and workers across the textile supply chain.

How to identify

Upland cotton is identified by its herbaceous to woody stems covered with sparse hairs, palmate leaves with 3-5 lobes (sometimes entire on lower branches), and serrated margins. Leaves are typically 5-12 cm across with prominent veins. Flowers are large (5-8 cm diameter), hibiscus-like with five cream-yellow petals that often have a purple to red spot at the base, lasting only one day before turning pink and falling. The distinctive fruit is a capsule (boll) 3-5 cm long that turns from green to brown as it matures, containing 25-45 seeds covered in dense white or cream fibers 22-32 mm long. Plants reach 1-2 meters in height under cultivation.

Habitat

Gossypium hirsutum thrives in tropical and subtropical regions with warm temperatures, full sun exposure, and well-drained soils. It requires frost-free conditions and grows best in areas with hot summers (25-35°C optimal), moderate humidity, and distinct wet and dry seasons. The species is cultivated in irrigated fields, river valleys, and plains with deep, fertile loamy or clay soils. Wild and feral populations occur in disturbed habitats, roadsides, and forest edges in its native range.

Distribution

Native to Mexico, Central America, the Caribbean, and possibly northern South America. Currently cultivated as a major crop across warm-temperate, subtropical, and tropical regions worldwide including the southern United States (particularly Texas, Georgia, and Mississippi), India, China, Pakistan, Brazil, Uzbekistan, Australia, and numerous African countries. It is the most widely grown cotton species globally, adapted to diverse climates from Mediterranean to monsoon zones.

Diet

Requires full sun (minimum 6-8 hours daily) and well-drained, fertile soils with pH 5.8-8.0. Needs moderate to high nitrogen, phosphorus, and potassium levels, with peak nutrient demand during flowering and boll development. Water requirements are substantial (700-1300 mm per growing season depending on climate), with critical periods during square formation, flowering, and boll filling. Tolerates some drought but yields decrease significantly without adequate moisture. Benefits from deep soils (minimum 60 cm) that allow extensive root development.

Behavior

Exhibits indeterminate growth with continuous vegetative and reproductive development under favorable conditions. Begins flowering 8-10 weeks after planting, with flowers opening in early morning and self-pollinating, though cross-pollination by bees and other insects occurs. The plant produces fruiting branches that bear flower buds (squares) that take about 3 weeks to develop into open flowers. After pollination, bolls require 45-65 days to mature. In natural conditions, the plant is a perennial, but commercial cultivation treats it as an annual with harvest occurring before frost. Responds to photoperiod and temperature cues, with flowering accelerated by shorter day lengths.

Reproduction & life cycle

Primarily self-pollinating but also cross-pollinated by insects, especially bees. Flowers are perfect (hermaphroditic) and open for one day, during which pollination occurs. Following successful pollination, the ovary develops into a boll containing typically 25-45 seeds. Each seed is covered by two types of fibers: long lint fibers (22-32 mm) used in textiles and short fuzz fibers. Bolls mature 7-9 weeks after flowering and split open (dehisce) along 3-5 sutures, exposing the fiber-covered seeds for dispersal or harvest. Seeds can remain viable for several years under proper storage conditions. In cultivation, plants are grown from seed annually, while wild plants can persist as perennials.

When to look

Planted in spring after last frost (April-June in Northern Hemisphere), flowers mid-summer (July-August), bolls mature and are harvested in autumn (September-November). In tropical regions with year-round warmth, cultivation timing varies based on rainfall patterns. Look for flowering plants in mid-growing season and distinctive white fiber-filled bolls in late season before harvest.

Cultural significance

Cotton has profound cultural and economic significance dating back at least 7,000 years in the Americas. It was independently domesticated in multiple regions and became central to textile production worldwide. The crop played a major role in global trade, colonialism, and the history of slavery, particularly in the American South. Cotton fabric production is deeply embedded in traditional crafts across cultures. Cottonseed oil is used in cooking in many regions. The phrase 'King Cotton' reflects its historical economic dominance. The cotton boll appears in symbols and flags of cotton-producing regions. Modern cotton production involves millions of smallholder farmers and remains crucial to economies of many developing nations.

Similar species

• Gossypium barbadense (Pima or Egyptian cotton)
• Gossypium herbaceum (Levant cotton)
• Hibiscus species (similar flowers but no cotton fiber)

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