Influence of Humic Acid in Diluted Nutrient Solution on Growth, Nutrient Efficiency, and Postharvest Attributes of Gerbera

A hydroponics experiment was conducted to study the effect of humic acid (HA) on gerbera (Gerbera jamesonii L.) cv. Malibu in different diluted nutrient solutions. The HA (500 mgL(-1)) was added to a nutrient solution (NS) of gerbera with two dilution levels of NS, 1/2 NS and 1/4 NS, and full-strength nutrient solution (NSc). The HA application compensated for nitrogen, magnesium, and iron deficiency in the 1/2 NS. Nutrient utilization efficiency (NUTE) of nitrogen in shoot decreased and that of Fe increased in the 1/2 NS compared with the 1/4 NS when HA was applied. The number of harvested flowers per plant was the greatest in the NSc and the 1/2 NS with incorporating HA. Flower vase life improved by increasing NS level (9.33 days). It seems HA could be successfully considered as a compound to decrease nutrients input in gerbera hydroponics production.