Hair finds new roots as urban farming growth medium

The clumps of discarded hair on the salon floor could one day help to grow your lunchtime salad, thanks to scientists from Nanyang Technological University, Singapore (NTU Singapore), who have created the growth medium used in urban farming – known as hydroponics substrates – using keratin extracted from human hair.

In hydroponics, crops are grown without soil, using a substrate that acts as both a support structure and a reservoir for water and nutrients. The keratin-based substrates developed by the NTU research team have been tested with crops such as microgreens and leafy vegetables, including the Chinese cabbage bok choy and arugula leaves, also known as rocket.

In their study, the NTU researchers first extracted keratin from human hair gathered from hair salons. The keratin solution is mixed with cellulose fibers to strengthen it, which is then dried into a spongy substrate.

The substrate is sustainable, biodegradable, and eco-friendly as it is made from waste material and becomes a source of nutrients for the plants as it degrades. The yield from this keratin-based substrate is comparable to materials currently available on the market, according to laboratory tests.

Professor Ng Kee Woei, associate chair at NTU's School of Materials Science and Engineering (MSE), who led the research, said, "Besides hair, livestock farming produces large amounts of keratin as biowastes, as it is found abundantly in wool, horns, hooves, and feathers. Since keratin can be extracted from many types of farm wastes, developing keratin-based hydroponic substrates could be an important strategy for recycling farm wastes as part of sustainable agriculture."

Image source: Zhao et al. (2022), ACS Sustainable Chemistry & Engineering.