Improved Biomass, Essential Oil, and Flavonoid Yield of Greenhouse Basil in Five Organic Soil Substrates.

Organic greenhouse production of valuable herbs in soilless cultivation is an attractive and economical alternative for high productivity and superior quality. However, adapted technology including information on substrates and fertilizer rates to maximize productivity and concentration of secondary compounds is needed. The objective of this study is to provide a quantitative measurement of the effects of biological amendments in organic greenhouse production of three cultivars of Ocimum basilicum (sweet basil) including O. basilicum cv. Genovese, cv. Thai, cv. Purple Petra, as well as O. suave cv. Mtule. Different combinations of coconut coir, composted pine bark, biochar, worm castings and composited chicken manure amended with or without beneficial bacteria and fungi are being evaluated. Measurements include pH, EC and microbial activity of the soilless mix combinations; and shoot and root fresh and dry weight, total phenolic content, and a-terpineol/eugenol concentration of basil plants. Preliminary results indicate a significant increase in shoot and root mass of O. basilicum cv. Genovese, cv. Thai in worm casting media and O. basilicum cv. Purple petra in biochar. Germination of O. suave cv. Mtule increased by 50% in biochar media. Insights gained from this study will help us understand how to implement organic substrates effectively in organic greenhouse herb production and will demonstrate the role of microbes in plant productivity. This knowledge will help growers improve organic greenhouse productivity and food quality.