Effect of organic substrate and aqueous extract of vermicompost on nursery basil growth

Organic substrates, including compost, are used in the production of commercial seedlings. In this study work, a commercial substrate (COS) was compared with compost made of cattle manure and onion residues (CCMOR) for basil (Ocimum basilicum L.) seedlings. In addition, the effects of irrigation with vermicompost tea (VT) prepared from urban solid wastes on seedling growth were studied. Half of these seedlings were irrigated with VT, while the other half only received water (W). Seedlings grown in COS irrigated with VT had the highest leaf area, height, and fresh weight in both years. Meanwhile, those growing in CCMOR irrigated with VT showed no differences in these parameters compared with those which received water. Also, the COS treatment plus VT produced plants with a higher chlorophyll content than those irrigated with water, in which the color parameters of leaves (L*, C-ab*, h(ab)) changed from dark green to light yellow during the growth process. Plants growing in CCMOR showed no differences in color and chlorophyll content when irrigated with water or vermicompost tea. Irrigation with VT produced seedlings with the highest content of N and K in the shoots grown on both substrates. The use of CCMOR as a substrate in the production of basil seedlings gave rise to smaller seedlings, with an increase in the marketing period compared to those grown on COS. Fertigation of basil with VT is promising because it increases the content of some nutrients in the aerial parts of the plant and improves the commercial aspect of this aromatic plant.