In the agrivoltaics pretrial in Wädenswil, lamb's lettuce was grown in three cultivation rounds (winter, early and late spring) under and behind ground-based solar modules to study their effects on crop growth. Leaf chlorophyll content was measured indirectly by means of the SPAD-502Plus Konica Minolta® chlorophyll meter. At harvest, specific leaf area (SLA) was collected from leaf punches and leaf length and width of single leaves and fresh weight of individuals were measured. The results

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... de significant differences in plant traits (chlorophyll content, leaf length, width, SLA) and harvestable fresh weight. Chlorophyll contents of lamb's lettuce leaves were significantly higher when grown under solar modules compared to the control and behind modules. Leaves were significantly longer and wider and had a higher SLA under solar modules (p < 0.05). Across all cultivation rounds, fresh weight under and behind modules increased by 17% and decreased by 8%, respectively, compared to the control. However, the influence of treatments strongly varied with season. Lamb's lettuces grown under solar modules had the highest fresh weight in cultivation round 1 and 3. Lamb's lettuces behind the solar modules had the lowest fresh weight in round 1 and 2. In cultivation round 2, fresh weight was identical for lamb's lettuce under the modules and in the control and slightly smaller in the zone behind the modules (-17%). In cultivation round 3, fresh weight increased by 67% and 16% under and behind the modules, respectively, compared to the control. Our findings suggest that beneficial effects of agrivoltaics on crop growth are possible andamong other factors of influence -depend on the season. In the case of lamb's lettuce, a preferential microclimate under solar modules can be assumed during winter months while its growing season may be potentially prolonged in late spring. Adverse effects were only observed in the area behind the modules with the lowest fresh weights in the first and second cultivation round.