Optimization of hydroponic production of the medicinal plants Euphorbia peplus and Artemisia annua in container

Production of leafy-green crops in indoor multi-layer hydroponic system with artificial light and controlled environment can be economically challenging. Cultivating high-added value crops such as medicinal plants may not be economically as difficult. Euphorbia peplus and Artemisia annua are medicinal plants with potential applications in para- and pharmaceutical sectors. Growing indoors in a controlled environment requires appropriate adjustment of abiotic factors to optimize crop growth. The objectives of the study were the optimization of the biomass of E. peplus and A. annua and the calculation of their cost price under indoor hydroponic cultivation systems. Shoot biomass, apical height, dry matter, foliar surface and the maximum quantum yield of primary photochemistry were measured under two nutrient solutions and three substrates for E. peplus, and under two light intensity and CO₂ levels for A. annua. Experiments on E. peplus were realized on 24-plants tray with 6 tray-repetitions per combination, for a total of 864 plants tested. Experiments on A. annua LSQUOs were realized on 12-plants tray with 2 tray-repetitions per combination, for a total of 96 plants tested. Results for E. peplus showed that no combination of substrates and nutrient solutions seems to be more effective for all the parameters tested, but the combination of one nutrient solution and rockwool allowed a better accumulation of shoot biomass and apical height. In the case of A. annua, a light intensity of 500 PPFD combined with CO₂ concentration at 900 µmol mol^‑1 allowed an increase of shoot biomass by 94% as compared to 250 PPFD and same CO₂ level. The cost of producing 1 kg of fresh shoot E. peplus and A. annua varied respectively from €146 to €198, and €66 to €121. Factors that influence the cultivation cost are discussed.