Overview
- U.S. researchers at Randolph‑Macon College report that pot mixes containing 25–50% dog hair produced roughly 2.5 times the plant weight of controls in basil, lettuce and marigolds, according to results published in MicroPubl Biol.
- In detailed metrics, basil grew about 150% more leaves, lettuce reached 50% greater diameter and marigolds formed triple the number of blooms compared with standard potting soil.
- Benefits are attributed to keratin in the hair releasing nitrogen as it breaks down and to improved root aeration from the fibers; washing the hair did not change outcomes.
- Coverage highlights the potential to replace peat in potting substrates, pointing to climate gains by limiting peat extraction and noting that hair waste from grooming salons is abundant.
- Conservation groups caution against scattering loose hair outdoors because birds may use residue‑contaminated fibers for nests, while the study indicates contained use in pots appears acceptable and calls for further research on residues, water retention, food safety and large‑scale practicality.