Humic acid and cultivar effects on growth, yield, vase life, and corm characteristics of gladiolus

Gladiolus (Gladiolus grandiflorus L.), a popular and economically profitable bulbous cut flower, has high demand in both Pakistan domestic and international markets on account of its attractive spikes, florets of huge forms, dazzling colors, varying sizes, and long vase life. However, its quality production is badly affected by non-uniform sprouting, poor crop stand, and old cultivars. To overcome these problems, an experiment was conducted to elucidate the effect of humic acid (HA) applied along with NPK (17:17:17) and five exotic cultivars of gladiolus, ‘Eminence’, ‘Cantate’, ‘Essential’, ‘Corveira’ and ‘Fado’, on uniform crop stand, growth, flowering, and quality of cut gladiolus. Among HA treatments, three applications of HA and NPK, applied at planting, 3-leaf, and 6-leaf stages of plant development, followed by two applications of HA and NPK, applied at planting and 3-leaf stage, proved best for early and uniform sprouting, more foliage growth per plant, greater leaf area, and total leaf chlorophyll contents, earlier spike emergence, greater number of florets per spike, longer stems and spikes, and greater diameter of a spike, higher flower quality, longer vase life, higher number of cormels per clump, and greater cormel diameter and weight. Plants grown without HA and NPK application (control) or application of NPK alone, applied at planting, had poor growth, reduced yield, and inferior quality. Among cultivars, ‘Fado’ performed best for commercial cultivation, considering the applications of HA.