Human Hair as a Nutrient Source for Horticultural Crops

Abstract

Two pot experiments were conducted to evaluate noncomposted hair byproduct as a nutrient source for container-grown crops. Lettuce (Lactuca sativa ‘Green Leaves’) and wormwood (Artemisia annua ‘Artemis’) were grown in a commercial growth substrate amended with 0%, 2.5%, 5%, or 10% by weight hair waste or controlled-release fertilizer (CRF) or were watered with a complete water-soluble fertilizer (WSF). After harvest, yellow poppy (Glaucium flavum) was grown in the pots and substrate that previously grew wormwood, and feverfew (Tanacetum parthenium) was grown in the pots and substrate previously containing lettuce. The 5% hair treatment and the commercial fertilizer rates were calculated to provide the same amount of nitrogen (N) during production of lettuce and wormwood based on 50% N availability from hair. Yields in treatments containing hair or CRF or watered with WSF were higher than in the untreated control. The highest lettuce and wormwood yields occurred with CRF followed by WSF and 5% and 10% hair treatments. However, yield of yellow poppy was higher in the hair treatments than yields in inorganic fertilizer treatments or in the untreated control. Feverfew yields did not differ among fertility treatments, but yields in fertility treatments were higher than those of control. Lettuce leaf moisture content was lower, but soluble solids were higher in plants in the hair waste treatments than in the WSF or CRF treatments. Total phenolics in lettuce did not differ among treatments. Total aerobic and coliforms plate counts were similar for all samples, averaging 6.0 and 1.2 log cfu/g, respectively. Results from this study suggest that noncomposted hair waste could be used as a nutrient source for container-grown plants. Hair waste should not be used as a single nutrient source for fast-growing plants because of the time needed for degradation of the hair before release of plant nutrients.