Benefits of organic fertilizer spray on growth quality of chili pepper seedlings under cool temperature

Abstract: Production of healthy, vigorous seedlings is necessary for optimum growth and high yields in field and greenhouse production of peppers. Pepper (Capsicum annuum) is a warm season crop and applying cooler temperatures during seedling growth may have some benefits, but it can reduce plant growth. In present study, effects of foliar application of synthetic and organic fertilizers were evaluated on growth and quality of chili pepper seedlings under greenhouse conditions with cool temperature of 15±3ºC. Treatments were foliar application of fertilizers in a 0.2 % concentration of: 1) N20:P10:K20, 2) Biomin (an organic aminochelate fertilizer), 3) Humifolin (a humic acid based fertilizer), 4) Biomin+Humifolin, 5) a synthetic macro-micro mixture, 6) soil application of NPK (600 mg.kg^-1 of the N20:P10:K20 formulation) and 7) a no fertilizer control. Fertilizer treatments improved seedling overall growth except for plant height and stem diameter. Most growth and quality traits were best improved by foliar application of organic Biomin aminochelate followed by Humifolin fertilizer. Higher values for leaf area, leaf number, chlorophyll index, root and shoot biomass, and leaf concentration of soluble sugars, N, K, Ca and Zn, were attributed to foliar application of Biomin aminochelate and Humifolin. The mixture of Biomin+Humifolin had reduced values of those parameters indicating possible negative interaction when these two organic fertilizers are mixed. So, under cool temperature foliar feeding of organic fertilizers (aminochelate) can effectively improve nutrients status and transplant’s quality of pepper.