GOhydro D1.2 - Report on Evaluation of Optimized Growth Environments in controlled Experiments (1st version)

Microgreens are plants at the young phenological stage between sprouts and baby greens, with a growing period of around 6-16 days from germination to harvest. They are gaining increasing attention because of their short production cycle and their beneficial attributes such as high nutrient density, secondary metabolite content, and gastronomic applications, all of which contribute to their categorization and use as ‘functional foods.’ Hence, the objective of this deliverable was to investigate experimentally the effects of nutrient solution fertilization, environmental parameterization, and light spectrum combinations and intensities on Biomass Yield and Secondary Metabolite Accumulation in five microgreen species and varieties: Ocimum basilicum (Basil var. Green Tesla), Sinapis alba (Mustard var. White Candy), Brassica oleracea var. sabellica L. (Kale var. Black Mandingo), Brassica oleracea (Radish var. Daikon Panzer), and Brassica oleracea convar. acephala var. gongylodes L. (Kohlrabi var. Red Cardinal). Our objective was to evaluate 12 different growth environments in controlled experiments conducted in a Climate Chamber in the University of Copenhagen’s Taastrup Campus, Taastrup, Denmark. These growth environments were designed to test microgreens production along a spectrum of environmental  conditions, from low-input to high-input, which will inform our larger GOhydro goals and later work packages. With this in mind, we chose to vary Relative Humidity (40 or 70%), Nutrient Solution (Yes or No), Light Type (Expensive or Cheap), and Light Quality (Recipe for Biomass Yield Max or Secondary Metabolite Max). The results of these experiments will provide important criteria for selecting optimal growth environments for microgreens within the context of GOhydro’s project goals. Because of supply chain disruptions due to the Coronavirus, our original light and climate chamber supplier experienced critical chip shortages resulting in indefinite supply delays. We therefore had to change our procedure by finding a new supplier and acquiring both new lights and a grow system from separate companies. This has resulted in an unavoidable delay in beginning the experimental stage of this deliverable given the equipment’s unavailability. In Deliverable 1.2: Evaluation of optimized growth environments in controlled experiments, we have therefore presented the deliverable’s background, our objectives, methods, results template, and the results of our analyses that were conducted on the dataset that was generated from our literature review conducted in D1.1: Review on nutrient and production parameters and light requirements. This analysis was undertaken via multilinear regression models, which will be used for the final version of D1.2. Our initial analysis showed that more variation in FW, DW, Carotenoid, Phenols, and Anthocyanin outcomes was explained by the light spectrum combinations than light intensity; this informed our experimental parameters that are set for D1.2. Given that we have already undertaken a similar analysis that has refined our methodology, including having ready R-code for analysis, D1.2 only needs data from our experiments to be completed.