Cotton is a fiber crop with a complex growth cycle. The duration from planting the seed to the final harvest of the mature cotton fiber typically spans a range of 140 to 180 days. This period encompasses a series of distinct vegetative and reproductive stages, and the total time is largely governed by accumulated heat.
The Initial Vegetative Phase
Planting requires the soil temperature to be consistently at least 60°F for successful germination. Under favorable conditions, the seedling emerges within 4 to 14 days. Initial growth focuses on establishing a strong root system, with the taproot growing rapidly to depths of 10 inches or more by the time the first true leaves unfurl.
The vegetative growth phase, characterized by the development of leaves, nodes, and branches, lasts for the first 6 to 8 weeks after planting. The first true leaves take over the process of photosynthesis from the seed leaves (cotyledons). Around 35 days after planting, the plant transitions to its reproductive phase with the appearance of the first “squares,” which are developing flower buds.
The Full Timeline from Planting to Harvest
The transition from a pinhead-sized square to a fully open white flower takes approximately 21 to 25 days. Once the flower opens, it is receptive to pollination. The fertilized flower remains open for about 24 hours, initially appearing white, but turning pink and then drying up a few days later to reveal the newly formed boll.
The boll is the fruit of the cotton plant, and the time required for it to develop from a flower to a mature, open boll generally lasts between 50 and 70 days. During the first three weeks of boll development, the cotton fibers rapidly elongate inside the boll, reaching their full length. For the next two weeks, the fiber’s secondary walls thicken, a process known as deposition, which determines the final quality and strength of the lint.
The final phase, called maturation, occurs when the boll reaches full size. Internal pressure causes the dried walls to split open, exposing the fluffy white cotton. Boll opening typically begins around 120 to 130 days after planting, with the entire field ready for harvest around 150 to 160 days.
Environmental and Varietal Factors Affecting Growth Duration
The range of 140 to 180 days for the total growth cycle is primarily due to external influences and the specific variety of cotton planted. Cotton is extremely sensitive to temperature, which is the most important factor in determining the speed of development. Growth stages are tracked using “DD60s,” or degree days above 60°F, which quantify the heat units the plant has accumulated.
Cooler temperatures significantly slow down the entire life cycle, causing the plant to take longer to accumulate the necessary heat units for each stage. Water availability also plays a major role, as drought stress or excessive moisture can slow down the development of new nodes and reproductive structures.
Cotton breeders have developed a range of varieties, often categorized as short-season or long-season types, to suit different climates. Short-season varieties are genetically programmed to complete their cycle faster, allowing farmers in regions with a limited number of frost-free days to achieve a successful harvest. Farmers select a cultivar that matches the length of their local growing season, ensuring the crop can mature before the onset of cold weather.