Actual Cost of Cotton Production Compared to Hemp Production

Although big names in the clothing industry are increasingly focused on lowering the cost of cotton clothing, the downside is that sustainability often suffers as a result. In order to get a better picture of this subject, we will try to shed some light on the entire process from plant to garment, for both the hemp plant and the cotton plant, to better understand the differences and benefits.

This whole process from plant to garment happens in both cases in a number of steps that are somewhat similar. However, the actual Co2 cost of both textiles is quite different. First, we will describe the process of how a cotton garment is made followed by the process of a hemp garment and finally, both processes will be put side by side to give a better idea of what it actually takes to produce the same amount of clothing from both plants. If you are curious about the results right away, there is a comparison between the two processes at the bottom of the article.

Cotton

First up is cotton. This process is divided into a number of steps.

1. Cultivation

The first step, of course, is the cultivation of the cotton plant. This entire process from sowing to harvesting takes about 160 days¹ for a cotton plant. During this process, the cotton plant emits a large amount of Co2. To put this into perspective, 1 ton of cotton emits about 1.8 tons of Co2² during its growth cycle. The irrigation of the cotton plant costs about 5.2 megalitres per hectare³. The use of pesticides is also necessary during the growing process. The cotton industry accounts for about 6%⁴ of the annual pesticides used each year. Globally, about 2.5 billion kg⁵ (2,540,117,272 kilograms) of pesticides are used annually. 6% of this is therefore about 152.4 million kg (152,407,315.14 kg) of pesticides per year. Since about 35 million hectares⁶ of cotton are grown annually worldwide, one hectare of cotton uses about 4.36 kg of pesticides (152.4 million / 35 million). Also, about 2x more land area⁷ is needed with cotton to make the same amount of textile compared to hemp. After this growth process, the cotton plant is harvested.

2. Ginning

This process, called ginning, begins with the drying of the cotton after which the cotton fibers are separated from the seeds. A ginning machine⁸ is used for this process.

3. Bale fibers

The cotton fibers are compressed into bales which are then sent to a textile mill for processing.

4. Spinning

The cotton fibers are then tightly twisted together to create thicker cotton yarn.

5. Weaving/knitting

The yarn is woven by interlacing the threads on a loom or knitted by interlocking the threads together using needles.

6. Dyeing

The fabric is passed through a hot dye solution and then pressed through rollers to remove excess liquid. This dyeing process is an incredibly Co2 expensive process. About 125 liters of water are used for 1 kg of cotton⁹. It also requires a lot of energy to heat and steam the water to achieve the desired result.

7. Cutting and sewing

The finished pieces of fabric are cut and sewn together to make clothing and other textile products.

This entire process is very labor-intensive and therefore a lot of machines and chemicals are used for this purpose to achieve the final desired result. Due to the development of the clothing industry that has long been focused on making everything as fast and cheap as possible, not much consideration has been given to making this process sustainable.

Hemp

The process of how hemp is processed into clothing has a number of different steps.

1. Cultivation

The hemp plant must also be cultivated, of course. For the hemp plant this process, depending on which article you consult, takes about 60 to 120 days¹⁰ and the hemp plant is known to be able to be grown 2 times a year as opposed to cotton which is grown once a year. Therefore, it can also absorb 2x as much Co2.  During this process the hemp plant has the ability to absorb more Co2 from the atmosphere than it needs to grow, about one and a half times as much. 1 ton of hemp absorbs about 1.63 tons of Co2¹¹. It is difficult to find the specific amount of water hemp needs per hectare. However, on the internet, you can find that hemp needs about 50% less water per season. Therefore one can assume that hemp uses 50% of the 5.2 megalitres of cotton which comes down to 2.6 megalitres per hectare¹². Hemp, unlike cotton, does not need pesticides to grow as the plant is naturally resistant to pests etc¹³. After this process, the hemp plant is harvested.

2. Retting

The hemp fibers are detached from the bark by the process of retting¹⁴. This involves breaking down the bark, which binds the fibers to the core of the stem. Thus, the long bast fibers are separated from the non-fiber components. This can be done naturally or with the help of enzymes.

3. Breaking

First, rollers are used to break the stems. Then the fibers are separated from the woody core. These fibers are used for textiles and the woody core is used to make other materials. Finally, the fibers are combed to align them and remove unwanted woody particles.

4. Spinning

After the fibers are made stronger by spinning them, the hemp fibers are spun together to make the thicker yarns, as is done with cotton.

5. Blending

This step is meant to mix the hemp with other textile materials such as organic cotton or wool to maintain the strength of the hemp yarn but make the final textile fabric softer.

6. Weaving/knitting

Similar to cotton, hemp yarn is woven by interlacing the threads on a loom or knitted by interlocking the threads together using needles.

7. Dyeing

In the process of dyeing the fabrics, it is difficult to find exactly how much water is needed. For this reason, we will just assume that this is the same as cotton. It is possible to find how much water is used to make 1kg of cotton garments and 1kg of hemp garments, therefore we will use this figure as the final comparison between the two textiles and leave out the water used in this process.

8. Cutting and sewing

The finished pieces of fabric are cut and sewn together to make clothing and other textile products.

As you can see, the entire process of processing the hemp plant into usable textiles is slightly different than cotton. It also varies from one factory to another how the hemp plant is processed. The idea behind this is that hemp textiles are basically very durable. However, a factory can of course choose to use bad chemicals anyway. It is also good to know that since hemp has a sustainable name within certain industries, many factories choose to keep the whole process as sustainable as possible since this is what the customer is usually looking for, a garment produced in a sustainable and responsible way.

Comparison

If you put the two processes next to each other, it quickly becomes clear what the differences in sustainability are with both plants. Below is a brief summary of the differences in sustainability between cotton clothing and hemp clothing that mainly takes shape during the growing process of both plants.

Growth period:

Cotton: 160 days

Hemp: 60 to 120 days

Co2 emissions:

Cotton: 1 ton of cotton emits 1.8 tons of Co2

Hemp: 1 ton of hemp absorbs 1.63 tons of Co2

Water use in cultivation:

Cotton: 5.2 megalitres per hectare

Hemp: 2.6 megalitres per hectare

Total water consumption¹⁵:

Cotton: 10.000 litres per 1 kg

Hemp: 2.719 litres per 1 kg

Pesticides:

Cotton: 4.36 kg per hectare

Hemp: no pesticides

It doesn't take an expert to see that there is a big difference in how both processes transform a plant into a garment for consumers. Since the development of cotton made great advancements in times when the industry was most important and sustainability did not apply, there was little to no focus on this. With hemp currently experiencing its own development, it is nice to know that this development is now primarily associated with making the process that transforms the hemp plant into a promising garment as sustainable as possible.

If it is difficult to find specific numbers for each fact since hemp has been able to experience a lot less research than other textile plants, many numbers on the internet differ from each other. Still, it is good to find your information on validated websites and remain skeptical about everything you read. So below is a source listing with where each figure came from.

Source listing cotton:

1. Cultivation

(Cotton, 2018)¹

(Farnworth, 2015)²

(Cotton Australia)³

(Claydon, 2021)⁴

(Alavanja, 2010)⁵

(WWF)⁶

(EasyEcoTips, 2021)⁷

2. Ginning

(Wikipedia-contributors, 2022)⁸

7. Dyeing

(Plug and Play Tech Center)⁹

Entire process:

(Dutfield, 2020)

Source listing hemp:

1. Cultivation

(Bennet, 2019) 60 days¹⁰

(Bellotto, 2022) 90 to 120 days¹⁰

(Grout, 2020)¹¹

(Palmer, 2011)¹²

(Kelly, 2020)¹³

2. Retting

(Wikipedia-contributors, Retting, 2022)¹⁴

Entire process:

(Vivek, 2021)

Total water consumption:

(Averink, 2015)¹⁵

Bibliography

Alavanja, M. C. (2010, September 27). Pesticides Use and Exposure Extensive Worldwide. Opgehaald van NCBI: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2946087/

Averink, J. (2015, September). Global water footprint of industrial hemp textile. Opgehaald van utwente.nl: https://essay.utwente.nl/68219/1/Averink,%20J.%200198501%20openbaar.pdf

Bellotto, M. (2022, February 4). Hemp is proving to be the fabric with the lowest ecological footprint. Opgehaald van Lampoon Magazine: https://www.lampoonmagazine.com/article/2021/03/28/hemp-fabric-lowest-ecological-footprint/

Bennet, C. (2019, February 25). How to Grow Hemp for CBD, Seed or Fiber. Opgehaald van thedailyscoop.com: https://www.thedailyscoop.com/news/retail-industry/how-grow-hemp-cbd-seed-or-fiber#:~:text=The%20plants%20grow%20rapidly%2C%20and,fiber%20is%20ready%20for%20harvest.

Claydon, S. (2021, December 10). Cotton. Opgehaald van Pesticide Action Network UK: https://www.pan-uk.org/cotton/#:~:text=Globally%2C%20this%20crop%20covers%20just,any%20other%20single%20major%20crop.

Cotton Australia. (sd). How Cotton Is Grown. Opgehaald van Cottonaustralia: https://cottonaustralia.com.au/assets/general/Education-resources/CA-resources/CEK_Chap_5B_How_Cotton_is_Grown.pdf

Cotton, B. (2018, August 22). The Journey of Cotton: Harvesting. Opgehaald van Barnhardt Purified Cotton: https://barnhardtcotton.net/blog/journey-of-cotton-harvesting/#:~:text=Cotton%20is%20fully%20mature%20and,the%20cotton%20plants%20for%20harvesting.

Dutfield, S. (2020, February 4). How is the cotton plant turned into clothes? Opgehaald van How It Works: https://www.howitworksdaily.com/creating-cotton-how-is-the-cotton-plant-turned-into-clothes/

EasyEcoTips. (2021, Februari 22). Hemp vs. Cotton clothes. Opgehaald van EasyEcoTips: https://easyecotips.com/hemp-vs-cotton/

Farnworth, G. (2015, September). Cool cotton. Opgehaald van Soilassociation: https://www.soilassociation.org/media/11662/coolcotton.pdf

Grout, L. (2020, December 26). Carbon Sequestration: Harvesting carbon from Hemp – Hemp Farms Australia. Opgehaald van Hemp farms Australia: https://hempfarmsaustralia.com.au/carbon-sequestration-harvesting-carbon-from-hemp/#:%7E:text=Throughout%20the%20120%20day%20crop,1.62%20tonnes%20of%20CO2.

Kelly, R. (2020, February 20). The Sustainability of Hemp. Opgehaald van The Hemp Pantry: https://www.thehemppantry.com/mainblog/the-sustainability-of-hemp#:~:text=Hemp%20can%20be%20grown%20with,commercial%20crops%20need%20to%20survive.

Palmer, B. (2011, April 12). High on Environmentalism. Opgehaald van Slate Magazine: https://slate.com/technology/2011/04/hemp-versus-cotton-which-is-better-for-the-environment.html

Plug and Play Tech Center. (sd). How Sustainable Dyeing is Changing the Textile Industry. Opgehaald van Plug and Play Tech Center: https://www.plugandplaytechcenter.com/resources/how-sustainable-dyeing-changing-textile-industry/#:%7E:text=Dyeing%20cotton%20is%20particularly%20water,necessary%20for%20the%20desired%20finish.

Vivek, V. (2021, December 5). Your T-shirt adds 6 KG of CO2 in Air. Know How Choosing Hemp can bring it down to Zero. Opgehaald van Hemp Foundation: https://hempfoundation.net/your-t-shirt-adds-6-kg-of-co2-in-air-know-how-choosing-hemp-can-bring-it-down-to-zero/

Wikipedia-contributors. (2022, May 5). Cotton gin. Opgehaald van Wikipedia: https://en.wikipedia.org/wiki/Cotton_gin

Wikipedia-contributors. (2022, May 5). Retting. Opgehaald van Wikipedia: https://en.wikipedia.org/wiki/Retting

WWF. (sd). Cleaner, greener cotton. Opgehaald van awsassets.panda: http://awsassets.panda.org/downloads/cotton_for_printing_long_report.pdf