3.3 Statistical analyses

In the beginning of the experiment were days until germination and germination rate counted. To be able to determine plant development, were randomly five seedlings of each light treatment measured weekly. The height (hypocotyl length + epicotyl length) of the plants, length and width of the biggest leaf was measured using a ruler. The number of leaves (a leaf was counted as a leaf when the length of the leaf was 2 cm or more) was counted. The diameter of the stem was measured immediately above the cotyledones using an electric digital caliper. The fresh yield of the leaves was measured and the fresh yield of the stem after cutting the stem at the substrate surface line. Samples were dried at 105°C for 24 h to determine dry matter yield of the leaves and dry matter yield of the stem. In addition, at the end of the seedling production was the dry matter yield of the roots (together with the rockwool cube) measured.

The leaf area of the biggest leaf was calculated as follows:  For tomatoes: Length of the leaf x width of the leaf x 0,347 - 10,7 (Blanco & Folegatti, 2003),  For sweet pepper: Length of the leaf x width of the leaf x 0,57 (Rodríguez Padrón et al., 2016),  For cucumbers: Length of the leaf x width of the leaf x 0,347 + 2,7 (Blanco & Folegatti, 2003) The ratio of dry aboveground biomass to height and the fresh and dry leaf weight to total biomass weight ratio was calculated. Energy use efficiency (total cumulative biomass yield in weight per kWh) was calculated for economic evaluation.

3.3 Statistical analyses

SAS Version 9.4 was used for statistical evaluations. The results were subjected to one-way analyses of variance with the significance of the means tested with a Tukey/Kramer HSD-test at p ≤ 0,05.