Cotton is a vital fiber crop for the textile industry and global economies. For farmers, knowing the precise harvest time is important, as it directly impacts fiber quality and quantity. The plant develops through distinct stages, each influencing the final product. Understanding these phases and the visual cues of a ready-to-pick boll helps ensure an optimal harvest.
From Bloom to Boll: Cotton’s Development
The cotton plant begins with germination and seedling establishment, followed by vegetative growth of its main stem and leaves. Around 35 to 47 days after planting, the plant enters the “squaring” phase, forming small, pyramid-shaped floral buds called squares. These squares are precursors to the cotton flower. Approximately 21 days after a square first appears, it opens into a flower, typically white or creamy yellow on its first day.
After pollination, often on the first day the flower is open, petals change color, usually turning pink or red, then wither and fall off within a day or two. The remaining ovary at the flower’s base develops into the cotton boll, the plant’s fruit containing seeds and fibers. This green, immature boll is segmented and contains immature seeds from which cotton fibers grow. Inside the boll, cells on the seed surface elongate, forming cotton fibers. These fibers grow and mature over the next month, filling the boll with fluffy lint.
Recognizing Ripe Cotton for Harvest
The definitive sign that cotton is ready for harvest is when bolls naturally open, revealing mature fibers. This process, known as boll dehiscence, occurs as the boll dries and its segments split. The outer casing, or burr, becomes dry and brittle, allowing the fluffy white cotton to expand. Optimally ripe cotton appears as a clean, bright white mass, fully fluffed and protruding from the dry, cracked burr.
Fibers should look uniform and free of green staining, which indicates immature plant material. The burr’s dryness indicates that the fibers have completed maturation and drying. Farmers often look for 50% to 60% open bolls before considering harvest aid applications or picking. Bolls that are still green, hard, or only partially opened suggest fibers are not yet fully mature or dry, negatively impacting quality if harvested too early. Conversely, bolls left on the plant too long after opening can be exposed to weather, potentially leading to quality degradation.