Cotton is a valuable global commodity, providing the natural fiber used in countless textiles worldwide. The timing of its harvest is not a fixed calendar date but a flexible window dictated by local climate, accumulated heat, and the plant’s biological maturity. This agricultural cycle is a cumulative process, requiring a specific number of warm days to ensure the fibers reach their optimal length and strength before collection.
The Cotton Growing Cycle
The journey from planting to harvest typically spans between 150 and 180 days, depending on the cotton variety and environmental conditions. Planting begins in the spring when soil temperatures consistently reach at least 60°F, usually between March and June in the northern hemisphere. After the seedling emerges, the plant enters a period of vegetative growth, quickly transitioning into the reproductive phase.
The first flower buds, known as squares, begin to form about 35 days after planting, marking the start of fruit development. A short-lived flower then appears, which, once pollinated, drops off and leaves behind the developing fruit called a boll. Each boll requires 50 to 60 days to fully mature, during which the cotton fibers grow and thicken inside the protective shell.
The final stage before mechanical harvesting is preparing the plant by removing its leaves, a process called defoliation. This is achieved either naturally by frost or, more commonly, through the application of chemical harvest aids. Growers apply these chemicals once approximately 60 to 75 percent of the bolls have naturally opened to reveal the white lint. Defoliation is essential because machines cannot efficiently pick the cotton fiber without excessive leaf material contaminating the crop and reducing quality.
Primary Harvest Timing
The primary cotton harvest season in the United States stretches from late summer through the end of the calendar year. The earliest harvests begin in the southernmost regions, while the latest occur in the northern and western parts of the Cotton Belt. This extended window accommodates the varying climates and planting dates across the major producing states.
For the majority of the US cotton crop, mechanical picking operations intensify from September through November. The harvest must be timed carefully to maximize the yield from open bolls while minimizing the risk of weather damage. Once defoliation is complete, farmers usually have a window of 10 to 14 days before picking can commence.
Dry, sunny weather is required for successful harvesting, as rain can significantly reduce fiber quality and delay the use of heavy machinery in muddy fields. The threat of an early-season frost, which can occur as early as late October in some areas, is a concern. A hard frost can damage unpicked bolls and stain the exposed fiber, making the speed of the harvest operation a high priority once bolls are fully open.
The harvest is often a multi-stage process, with the main picking focused on the highest-yielding, fully open bolls. Following this, some fields may undergo a second pass, sometimes called “scrapping,” to collect any remaining, lower-quality cotton. Harvesting must be completed before winter weather permanently damages the remaining fiber, making late November and December the final deadline for many northern fields.
Regional Differences in Harvest Dates
The geographic spread of cotton cultivation means that harvest dates can shift by several months across different states and international regions. In the United States, the harvest begins earliest in the deep south of Texas, where warmer conditions allow some fields to be picked as early as July and August. The season then progresses northward and eastward as plants reach maturity.
In the Southeastern states, such as Georgia, Alabama, and the Carolinas, the harvest typically occurs from September into November, influenced by summer rainfall and the potential for late-season tropical storms. Conversely, the Western states, including California and Arizona, often have a later, more compressed season, with most harvesting taking place from October through December. These regions often grow Pima cotton, which has a slightly different maturity timeline than the common Upland varieties.
Globally, the harvest timeline is reversed in the Southern Hemisphere due to the opposite seasons. Countries like Australia, Brazil, and Argentina plant their cotton around November and December, leading to a harvest season that runs from March through August. This counter-seasonal production helps ensure a year-round supply of cotton fiber to the global market.