I’m willing to bet most of us come into contact with cotton multiple times per day. You might be wearing it right now. Yet how many of us have ever seen a cotton plant (Gossypium spp.) in person, let alone grown our own?
Home-grown cotton is highly regulated in some areas in order to protect industrial-scale crops that may be growing nearby. However, you still might be able to grow it yourself if you have the space and the suitable climate.
In this article, I’ll break down the core cotton plant growth stages and introduce you to the world of home-spun cotton for possibly the first time!
Conditions for Growing Cotton
Cotton is native to arid, warm climates found in several parts of the world (historical evidence of cotton plants has been found on all continents except Europe and Antarctica). Cool winters tend to be the biggest obstacle keeping gardeners from cultivating cotton at home.
According to the USDA, cotton can only grow in areas where there are at least 180 frost-free days each year. This more or less translates to Hardiness Zones 8 and above. (Though some years in Zones 6 and 7 provide 180 frost-free days, there’s little room for error.)
Cotton is usually grown as an annual crop in the United States and similar climates. Botanically speaking, however, the plant has a perennial life cycle and can live up to 5 years.
Outside of these requirements, you can treat cotton similarly to any other vigorous garden crop. Cotton likes full sun and rich soil with plenty of organic matter to support its growth.
You can even grow cotton plants indoors; know that you’ll need to invest in a grow light! This might be a way to get around increasing restrictions in some areas but be sure to check your local guidelines first.
Cotton Plant Growth Rate
Cotton requires a more extended season than any other annual-planted crop in the United States. This tracks, given cotton’s need for almost six months of frost-free growing conditions!
Farmed cotton typically reaches a height of up to 5 feet before harvest. Particularly vigorous plants may grow up to 1 foot per month. Wild cotton, on the other hand, can grow over 15 feet tall over the course of several years.
Life Cycle of a Cotton Plant
So, we know that cotton takes 160 to 180 days to reach maturity. But what processes is the plant going through during that time?
Here’s a quick look at the growth stages of a cotton plant in the context of a home garden or industrial farm:
1. Seed Germination
Growing cotton typically starts with planting seeds. These seeds can be purchased just like tomato or pepper seeds but may not be for sale in all areas due to local laws and restrictions.
Cotton wastes no time once planted. In the right environment, young seedlings may emerge from the soil in just 4 to 5 days.
According to Texas A&M University, cotton seeds can start germinating once the soil temperature reaches 60°F but much prefer temperatures of at least 65°F at depth. Temperatures below 50°F can damage the germinating seeds.
Cotton plants are categorized as dicots, meaning (among other things) that each young seedling starts life with two primitive leaves called cotyledons. Cotyledons provide a source of stored energy for the baby sprout in the time between germination and the development of the first true leaves.
A cotton plant’s true leaves resemble the adult foliage and are capable of photosynthesizing. The first of these leaves should appear within 14 days of sprouting.
(Cotton cotyledons perform a little bit of photosynthesis, too, which isn’t true in all plants. However, the cotyledons can’t keep up with the immense energy needs of a growing cotton seedling for longer than a few days!)
3. Vegetative Growth
The vegetative growth stage is all about laying down a strong, healthy foundation both above and below ground. Cotton forms a shrubby structure with a solid main stem and many side branches. New leaves will develop along these branches as the plant matures.
Cotton plants generally flower about 50 to 60 days after planting if everything goes to plan. The flowers form on special ‘fruiting branches’ that typically emerge near the top of the plant.
Cotton flowers are white to buttery yellow and turn pink as they age. They sort of resemble hibiscus blooms (both plants belong to the Mallow family). Depending on the climate, flowering can last for 30 to 60 days.
Each flower only lasts for about a day before the reproductive structures fall off. Cotton is mainly self-pollinating but visiting bees and other insects have been shown to improve yields.
5. Boll Development
It’s now time for the most critical phase of the cotton life cycle: boll development. Bolls are the plants’ fruit and contain the valuable fibers that cotton is grown for. According to Bayer Crop Science, this process is broken up into 3 stages:
- Enlargement — The fibers attached to the seeds inside the boll develop and elongate. This stage lasts about 21 days.
- Filling — The cotton fibers continue to mature, is sometimes known as deposition. This takes about 14 days.
- Maturation — After the fibers mature and the boll reaches its full size, the fruit walls break open and reveal the white fibers inside.
When to Harvest Cotton
Depending on climate and weather conditions, the cotton harvest period can last from summer all the way to early winter. In any given area, harvesting can take place over 6 or so weeks as new bolls reach maturity.
It’s easy to tell when cotton is ready to harvest as the bolls will burst open and reveal the soft, white fibers inside.
If you have enjoyed this article, you may also be interested in Turmeric Plant Growth Stages.
FAQs Cotton Plant Growth Stages
Why is it illegal to grow cotton?
Growing cotton at home is restricted in some parts of the world where cotton is typically grown agriculturally. This ban is meant to protect industrial cotton crops from diseases and pests (like the cotton boll weevil) that home gardeners may accidentally spread.
- U.S. Department of Agriculture (USDA) Cotton plant growing requirements
- Texas A&M University Cotton seed germination temperatures
- Bayer Crop Science Stages of Cotton Boll Development
Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.