Human hair, discarded in barber shops, can become a good fertiliser when combined with compost.
Researchers Vlatcho D. Zheljazkov, Juan L. Silva, Jelena Stojanovic, Youkai Lu, Taejo Kim and Thomas Horgan of Mississippi State University have published a study designed to determine whether commercially available noncomposted hair waste cubes would support plant growth in horticulture crops as a sole source of nutrients.
The study compared the productivity of four crops: lettuce, wormwood, yellow poppy, and feverfew, grown in commercial growth medium using untreated control, noncomposted hair cubes at differing weights, a controlled-release fertiliser and a water-soluble fertiliser.
Results showed that, with the addition of hair waste cubes, yields increased relative to the untreated control but were lower than yields in the inorganic treatments, suggesting that hair waste should not be used as a single source for fast-growing plants such as lettuce, said a university release.
Zheljazkov suggests that "once the degradation and mineralisation of hair waste starts, it can provide sufficient nutrients to container-grown plants and ensure similar yields to those obtained with the commonly used fertilisers in horticulture.
"However, it takes time for the hair to start degrading and releasing nutrients, as is reflected in lower yields in the hair treatments relative to the inorganic fertilisers for lettuce and wormwood."
The study appeared on the ASHS HortTechnology electronic journal website.