Hemp vs Bamboo Rayon for Cloth Diapers

We get a lot of questions from customers in the bynature.ca store asking why they would want to choose bamboo vs. hemp for cloth diapers. Short answer: choose hemp for environment or absorbency, and choose bamboo rayon for softness.

Overall, we prefer hemp. In our completely unscientific survey of Facebook followers,
parents choose hemp 8 to 3. But, parents who love bamboo rayon diapers really love them. That’s fine, of course! Use what you love.

What’s the difference between bamboo and hemp?

Bamboo and hemp are both woody plants that grow easily without the kind of chemical inputs (pesticides, fungicides) and the heavy watering needed by cotton. On a microscope level, each little hemp fiber even looks a bit like a bamboo stalk with smooth areas between knobby spots. So far so good.

For parents who have used both fibers in diapers, you will notice the difference in feel (bamboo is very soft while hemp is more stiff) and function (bamboo is absorbent but not nearly as absorbent as super soaker hemp).

For parents looking to lower their environmental impact, the biggest differences between bamboo and hemp are in the processing of fibers used in cloth diapers. Bamboo is broken down into pulp, chemically processed and aged, then extruded as a rayon fiber. This is a long (often years long) process that involves a lot of chemicals. Bamboo rayon is a synthetic fiber from natural inputs. Hemp is mechanically processed, aided by natural enzymes and chemicals. The hemp fibers spun into yarn are the natural fibers from the plant. Most of the story of impact is in the process, and there are certainly manufacturers working to lower the impact of processing for both fibers. What you have available to you right now is a high-impact rayon that is currently very popular and marketed as eco-friendly and a lower-impact hemp that is perhaps not as popular as it has been in the past decade and not marketed as heavily.

How rayon fibers are made from bamboo

Rayon made from bamboo. To make the bamboo rayon fibers used in diapers, the soft parts of the bamboo plant are crushed into pulp. Wood pulp and pulp made from other cellulose fibers can also be used to create rayon (or viscose, as regular rayon is called). The pulp is then dissolved, dried, sent through several phases of aging and ripening, cooking and burning before being extruded into long fibers. Think of extrusion as forcing pasta dough through a spaghetti press. Chemicals are used in many of these steps to create a material that can be extruded and hold together as a fiber. A lot of the negative publicity about bamboo focuses on these chemical processes. After extrusion, the fibers are bathed in sulfuric acid, stretched, and washed. Then, you have rayon filaments that can be knit or woven into a fabric.

Bamboo can be processed in a closed loop, so the solvents are captured rather than waste. Because of the popularity of fabrics made from bamboo, there are a lot of companies working to develop more eco-friendly processes. There are also efforts to add nano-particles of charcoal to make the fiber antibacterial.

For now, any fiber made from bamboo cellulose but be labelled “rayon” or “rayon made from bamboo” in order to comply with U.S. Federal Trade Commission guidelines. (“Have You Been Bamboozled?” FTC, January 4, 2013.)

Linen made from bamboo. There is also a form of bamboo processing that is closer to that of hemp. The woody part of the plant is crushed, and an enzyme is used in the retting process, breaking down the rough outer layers to get to the softer inner layers. Those softer, inner fibers can then be spun into yarn. Unless your diapers are labelled “linen made from bamboo,” they are made from “rayon made from bamboo” (and we don’t know of any cloth diapers made from bamboo linen).

Source of bamboo. It’s great that bamboo can grow easily in some places where other plants can’t. The environmental and social problems happen when the demand for bamboo rayon is so high that forests are cut down to plant bamboo, people are pushed off their land for bamboo, or bamboo is grown in monoculture. What CAN be done in bamboo cultivation isn’t necessarily what IS done, so we need to look at the provenance of our fibers. Most bamboo is used in fabric production is grown by one massive company in China, which grows the fibers to Oeko-Tex 100 standards, but many manufacturers of textiles made with bamboo rayon claim to process their own fibers outside of that system. It matters where and how bamboo is processed, so ask your cloth diaper manufacturer. If they don’t know about the process used, they should be able to follow the chain to their suppliers and find out.

Antibacterial? The U.S. FTC says bamboo rayon fabric does not have antibacterial qualities as often marketed, while many manufacturers continue to claim antibacterial properties and testing that proves it. The legal battles are still underway, so it’s fair to be skeptical of both claims for now.

How hemp fibers are made

The process of making usable yarn from hemp is similar to that of making linen from bamboo. The stem of the hemp plant is wound with heavy fibers. An enzyme is used in retting, and the softer (though not necessarily soft) fibers are spun into yarn. The softness of hemp depends on the point in the season or growing process when the hemp is harvested. Those who work with hemp often can tell the difference between the softer, early season hemp and the stiffer, late season hemp.

Hemp is generally mixed with other fibers. The hemp most often used for cloth diapers is 45% hemp / 55% cotton, taking on the absorbency of hemp and the softness of cotton. To use 100% hemp in a diaper would give a stiffer feel like linen, though it is possible to made a very soft hemp linen by using only the finest fibers.

Quick Comparison of Bamboo and Hemp for Cloth Diapers

Bamboo
PRO

• soft to the touch in the product,
• renewable fiber,
• lower impact than petroleum-based fibers,
• easy to grow in the field,
• can be made in a closed system to reduce environmental impact

CON

• often greenwashed in deceptive or uninformed marketing,
• chemically processed to create rayon,
• environmental injustices in meeting the recent demand,
• more sensitive fiber than cotton or hemp to detergent chemicals and drying heat of cloth diaper laundry,
• many manufacturers recommend line drying to avoid dryer heat,
• can be damaged by some basic laundry detergent ingredients (like baking soda)

Hemp
PRO

• very absorbent in the product,
• renewable fiber,
• lower impact than petroleum-based fibers and other plant-based fibers (cotton and bamboo),
• easy to grow in the field

CON

• stiffer to the touch than bamboo rayon or cotton,
• so absorbent that it can retain stink in diapers if not rinsed properly,
• needs more water in laundry process,
• can be difficult to maintain in HE (high efficiency) washer

Why Choose Bamboo vs. Hemp?

In the end, whether you choose bamboo rayon or hemp for cloth diapers depends on your priorities.

• If you are looking for a soft diaper, choose bamboo rayon. It is super soft and silky to the touch.
• If you are looking for lower environmental impact, choose hemp. It is easy to grow in the field. Although there is usually a chemical process to soften the fibers for spinning (though hemp can be mechanically processed), this is a much less problematic process than that of breaking down bamboo.
• If your laundry detergent includes baking soda, choose hemp (or change detergents). Baking soda will damage bamboo diapers, beginning the process of breaking down the cellulose.
• If you are looking for an absorbent diaper, choose hemp. Hemp is a super absorbent fiber.
• If you are trying to give your baby a stay-dry feeling without petroleum products, choose hemp. Because of its absorbency, the surface feels more dry than other fibers holding the same amount of liquid.
• If you have an HE washing machine, choose bamboo rayon—or cotton. Hemp is so absorbent that it requires more water in washing and rinsing to keep it soft and clean. But, be careful with bamboo rayon in an HE washing machine, because it is important that it be rinsed well.
• If your water is very hard, skip both hemp (because it can retain mineral build up) and bamboo rayon (because it is sensitive to the chemicals you need to use to wash in very hard water and can break down in the heat of the dryer if those chemicals aren’t rinsed well), and choose cotton.

We LOVE hemp in the bynature.ca store for many reasons, but we are always answering questions for customers about bamboo rayon—and why we don’t stock more of it. From an environmental standpoint, hemp has bamboo beat. In diapers, when it comes to absorbency and the natural stay-dry feeling, hemp also excels. The soft and silky feeling of bamboo is hard to resist though!

Image © Les Cunliffe | Dreamstime.com