Cotton is an extremely useful plant providing us with a natural fabric with a plethora of uses. Though it is not usually grown in the UK, a carefully planned polytunnel might allow us to grow a cotton plant even in our climate.
Key Information
There are four main plants that provide fibre for commercial fabric, the primary one being Gossypium hirsutum, or upland cotton. Upland cotton is native to Central America, Mexico, the Caribbean and Southern Florida.
There is one other cotton from the so-called New World, Gossypium barbadense, which comes from the neo-tropics of South America. The other two, Old World Species, are Gossypium arboreum and Gossypium herbaceum. The former of these two comes from India and Pakistan, the latter from Southern Africa and the Arabian peninsula.
Cotton is not grown commercially in the UK, though the production of cotton fabric and the import and export of the material and cotton fabrics is very much a part of British history of Empire and colonialism – including, unfortunately, being very much enmeshed with the atrocities and injustices associated with Empire and colonial expansion and exploitation.
Unfortunately, the cotton growing industry today is still fraught with a range of moral issues. Forced labour and slavery, pollution, excessive water use and degraded soil are just some of the problems with cotton cultivation around the world.
Growing your own cotton is a way to ensure that it has been grown organically and in an ethical way – though realistically it is more likely to be a novelty than any serious enterprise in our climate – even with the benefit of a polytunnel.
Sow and Plant Cotton
Sow cotton indoors early in the year. This is essential in order to allow the crop to mature by the end of the season. This plant needs around 130-150 days from sowing to reach the stage of harvesting.
Even in a polytunnel, it will be a challenge to get the crop to mature in time, simply due to the conditions. Though a polytunnel brings us closer to the conditions in which cotton plants will thrive, it will still be difficult to provide ideal conditions.
Start the seeds inside your home, ideally in a heated propagator that will consistently provide high enough temperatures for the seeds to germinate successfully.
The young plants can then be planted out into their final growing positions in the polytunnel once there is no longer any risk of frost and the weather has warmed reliably.
Or they can potentially be grown on in pots.
Where and When is Cotton Grown?
Cotton is typically grown in the tropics and subtropical regions, which is why it can be challenging to grow it in our cool, temperate climate here in the British Isles. The most important areas of production for cotton are China, India and the United States.
Typically, cotton is grown in summer, with planting between April and June depending on the specific location, and harvesting between August and late September.
Optimal Conditions to Grow Cotton
If you want to attempt to grow a cotton plant in a temperate climate polytunnel, you first have to understand the conditions that the plant requires. We need to mimic the conditions to be found in the best cotton growing regions as closely as possible in order to provide the plant with what it needs.
Climate Requirements: Temperature And Precipitation
Cotton needs:
- Temperatures of 22 – 36°c, but the plant can tolerate temperatures between 15 and 42°c.
- Humidity that is medium to high.
- Full sun conditions.
- Rain/ or irrigation to mimic 750 – 1,200mm per year. This is the preferred range but cotton tolerates 450 – 1,500mm per annum.
- A long, hot growing season with abundant moisture followed by a drier period for harvesting the seed floss.
- Well drained, fertile soil or growing medium, with a pH between 6 and 7.5.
Practices of Cotton Sowing
Cotton can either be sown in pots indoors for later transplantation, or sown directly where it is to grow. The former is the best option in the UK where we are challenged by a short growing season, even in a polytunnel.
It can be very difficult to provide temperatures that are warm enough further north in the UK, but some very mild and sunny southern gardens may successfully grow a cotton crop from seeds that are direct sown.
How to Grow Cotton Outdoors
Where cotton is grown outdoors, in zones 8-10, it can be sown directly after the last frost in your area. In zones 5-7 it is best to treat like tomatoes and sow indoors for later transplantation.
If you are attempting to grow cotton commercially, the plants are planted or seeds sown at stations positioned 45-80cm apart, in rows around 1.5m apart.
How to Grow Cotton Indoors
Most commonly, cotton will need to be sown indoors to grow a plant successfully in the UK, because we need to extend the growing season in order to get a harvest, however small, before the weather turns too cold for the plant.
Sow cotton seeds in spring into pots filled with a peat-free growing medium that is moist but free-draining. At temperatures of 21 degrees C., the cotton seeds should germinate within 1-3 weeks.
Be sure to harden off cotton plants grown indoors before you transfer the seedlings to your polytunnel garden.
In the polytunnel, the young cotton plants can be planted into the ground or into containers. Cotton plants will grow up to around 2m in height and spread in ideal conditions. Make sure you choose a container large enough to accommodate the plant.
Notes
Cotton thrives on heat, but does not respond well to overwatering. Make sure that conditions are sufficiently free-draining.
In cool climates, it can be a good idea to grow individual cotton plants in large, dark-coloured containers since the dark surface of the container will absorb heat and help to increase root warmth.
There are other fibre plants that you can grow instead of cotton. Both commercially and at home, some fibre plants to consider for clothing and other fabrics are hemp, flax and nettles, all of which are used to create sustainable natural fabrics here in the UK and in other temperate climate regions.
Harvesting
Of course, cotton has many uses. The seed floss is the main commercial harvest. It is used for clothing of course, and has a range of other fabric uses too. The floss is harvested once the bolls break open showing the fluffy clouds.
An oil is also derived from the seeds, and waste from this process used as a manure. The seeds are edible, nutty in flavour when roasted. They can sometimes be eaten as a snack or boiled and used like rice in soups, stews and the like. In some forms, however, note that the seeds contain a toxin that must be removed before they can be eaten.
How to Care for Cotton Plants
The main battle when caring for cotton plants is trying to provide sufficiently warm, sunny conditions. You always need to bear their environmental needs in mind when considering any element of their care.
Above and beyond making sure that you need the environmental needs listed above, here are some other tips to help you care for cotton plants correctly.
- Sow indoors and harden off seedlings before transplanting.
- Warm soil or growing medium before planting with cloches or row covers.
- Provide consistent water but water carefully, take care not to overwater and ensure that waterlogging cannot occur.
- Mulch around plants upon planting, and provide a regular liquid feed throughout the growing season to ensure good results. Apply a nitrogen-rich organic plant feed a couple of weeks prior to the first flowers and again a couple of weeks after the first flowers form.
- Mulch or feed to provide cotton with micro-nutrients required and to give the plant a boost.
Preventative Pest and Disease Control
In addition to the above, you also need to remain vigilant and look out for any pests or diseases that might trouble your cotton plant.
Different pests pose risks at different stages of cotton growth:
- from seedling to fourth leaf emergence: grasshoppers, cutworms, thrips, aphids, and jassids;
- from squaring to bloom: spider mites and plant bugs;
- from bloom to harvest: cotton bollworms, European corn borers, fall armyworms, tobacco budworms, whiteflies, cabbage loopers, stink bugs.
Plants can also be infected by endemic bacteria, fungi, and viruses. Among the most serious crop diseases are anthracnose, leaf spot, leaf curl disease, Fusarium and Verticillium wilt, root and boll rot, and bacterial blight.
Providing optimal growing conditions to keep your cotton plants as healthy as possible, companion planting and boosting biodiversity can all be strategies for holistic and sustainable pest prevention and pest control.
How Long Does Cotton Grow?
Large yellow flowers appear on cotton plants around 45 days after sowing. The flowers then wither and drop off and bolls form.
Stop watering 16-18 weeks from sowing when bolls have been formed, so that the plant begins to dry and shed their leaves, and the cotton boll will split open to form a fluffy ball.
Cotton is sometimes a perennial plant (depending on the specific species) but you will almost certainly need to grow it as an annual plant in the UK, since temperatures drop far too low over winter for successful cultivation – even with the protection of a polytunnel.
FAQs
How long does it take to grow cotton from seed?
It takes approximately 130 to 150 days, or 16-18 weeks, for cotton to grow from seed to harvesting. Though the exact amount of time that it will take will depend on the temperatures and other environmental conditions, and your specific location.
Can you grow cotton in a greenhouse or polytunnel?
In temperate climates, growing in a greenhouse of polytunnel means that you might be able to provide conditions that work for these tropical/ subtropical plants. In a greenhouse or polytunnel, cotton can be grown in many places where it would not thrive outdoors.
Can Britain grow cotton?
Cotton cannot really be grown commercially on a large scale outdoors in the UK. However, while we do not have the right climate to grow cotton, we can potentially grow a few plants in greenhouses or polytunnels here in the British Isles.
For commercial fibre production, it is more useful to consider climate appropriate natural fibre plants like nettles, and hemp, and flax for linen, for example.
Is cotton easy or hard to grow?
Cotton is very challenging to grow here in the UK because it is not well suited to the climate and conditions that we can naturally provide. However, it is certainly possible, with some effort, to grow a cotton plant successfully in a polytunnel garden.
Sources
Makhula, A. T., (2020) 33 Uses of Cotton. Engineering Textile.[online] Available at: https://engineeringtextile.com/fiber/169-uses-of-cotton
