As the name suggests, TPU fabrics are made using a (slightly more expensive) heating process that ‘bakes in’ the laminated waterproofing properties rather than using a chemical cocktail to achieve the same, as in PUL. At GroVia, we chose TPU for the outer layers of our Hybrid Shells, both of our All in One diapers, and even for the backs of our cloth Soaker Pads. We just think it’s too important—for our babies and for the planet—to risk the possibility of trace solvents lingering in fabric and ‘coming out in the wash’ each time we do laundry.

Bamboo fiber is a very absorbent material that is said to naturally resist the growth of bacteria. It is derived, of course, from the bamboo plant, a super-fast growing species that can be farmed sustainably. Sounds like a great choice for cloth diapering, right? Well, yes and no. Sustainable farming is certainly a major upside, but, unfortunately, the process required to convert bamboo pulp into the soft and absorbent cloth that is found in clothing and cloth diapers is complex and chemical-laden, so much so that it may do more environmental harm than the good achieved by the sustainable farming of bamboo crop. Because of the manufacturing process, bamboo fiber can never rightfully be labeled ‘organic.’

Cotton is quite simply the most-used plant fiber on the planet. It’s absorbent, has many uses, and is hands-down the most popular fabric for making cloth diapers. Because of its widespread popularity, cotton farming and production has been a major industry for a very long time, and the ‘industrial’ form of the cotton business is one of the biggest users of pesticides on earth. As in most business arenas, the name of the game for conventional cotton is yield: the higher, the better. For this reason, industrial growers rely on the heavy use of water (for irrigation), pesticides, and sometimes even GMOs (genetically modified organisms) to do what they call ‘improving’ their business—even though ALL of these practices have a negative impact on farmlands over time. Luckily, you have choices. And so do we.

To seek a remedy to these issues, more and more apparel and, yes, cloth diaper brands are beginning to use organic cotton, which is grown with lower overall impact and without any pesticides. If you want to ensure that the cotton in your diapers or clothing is produced in the most responsible way, make sure to review or ask about your manufacturer’s organic certification process. Without a certification (like GOTS) in place, there is no guarantee that the cotton you are buying is actually organic. If you’re interested, you can read more about GroVia’s certification program. Organic cotton is often more ‘fragile’ than its conventionally farmed or polyester counterparts, and it will almost always show wear after about 100 washes.

Hemp is another natural fiber that is said to resist bacteria growth. It is more hygroscopic (water-holding) than cotton, and it is usually grown in a low-impact manner, using less water and other resources than is used to farm cotton. While they have the ability to hold more water than cotton, hemp’s textile forms are quite thin and stiff, and they do not absorb water as quickly as cotton or polyester. To overcome this issue, most diaper brands that use hemp (like GroVia) will combine hemp with another fiber, so you will usually see ‘hemp/cotton blend’ on the care tag.

Modal fabric has some similarities to bamboo, especially since it is made from wood pulp—in this case from beech trees instead of from the bamboo plant. Modal has become more popular in recent years in a wide variety of apparel, probably because it has an awesome, silky feel and because it wears well and maintains its softness over time. It is also another highly absorbent cloth, holding up to 50% more water than a comparable amount of cotton. Over time, modal fabrics tend to be resistant to mineral build-up, making them a potential solution for cloth diaper users who must launder in hard water. Because of the manufacturing process that reconstitutes the wood fibers, modal is another fiber that can never be properly labeled ‘organic.’

Polyester is a well-known man-made material that is produced using a variety of chemicals and petroleum materials. You will often see the word polyester used interchangeably with terms like ‘minky,’ ‘microfiber,’ ‘microterry,’ and occasionally something called ‘Zorb.’ The upsides to polyester in cloth diapering are that it can be used immediately (no prepping needed) and it can put up with a lot of abuse—like being laundered multiple times per week. Most polyester fabrics start out as quite absorbent, and they have a reputation for durability. But they can wear out over time, losing their ability to absorb and hold as much water as they once could. Most absorbent polyesters cannot be worn directly against a baby’s skin because they will irritate their sensitive skin, and their structures can make them more difficult than natural fibers to keep clean, often leading to sustained odors.

A particular form of polyester, fleece comes in a variety of weights and can perform a host of functions. Thin fleeces are often used on the interior of a diaper as a ‘stay-dry’ layer (described below), while thick fleeces are sometimes used to make breathable diaper covers. Because fleeces can be simultaneously water-resistant and breathable, they can make for a very comfortable and flexible diaper cover. Fleece does vary in quality, however, and can sometimes create what is called ‘compression leaks’ (think of a wash cloth being wrung out when your baby sits on it) if used in a car seat or baby carrier for an extended period of time.

As mentioned above, thin fleeces are often used to create a ‘stay-dry’ layer inside of diapers. This layer is designed to wick moisture away from a baby’s skin and into more absorbent materials underneath this layer. In cloth diapers, you will often see the term ‘stay-dry’ used interchangeably with specific textile names like ‘suedecloth’ and ‘microfleece.’