Comparison of two pilot cropping systems for vertical cultivation of lettuce

Sammanfattning: Commercial cultivation of greenhouse crops is today dominated by horizontal hydroponic cropping systems. But with greater demand for local food production, increased urbaniza-tion and expanding cities creates an interest of improved space utilization and crop optimi-zation per square meter. This study was initiated to investigate the possibility of vertical cultivation of lettuce. Two pilot cropping prototypes, P1 and P2, designed for vertical cul-tivation of lettuce were compared to define the potentials and limitations for commercial lettuce production. Results look promising and both P1 and P2 showed potential produc-tion of lettuce (Lactuca sativa, Lollo rosso, cv. fortress) with respect to canopy fresh weight. Lettuce with acceptable commercial size was produced. The results also showed that light intensity is the limiting factor in terms of crop size and to produce a uniform crop in vertical cropping systems. Conclusion is that both prototypes P1 and P2 are interesting candidates for cultivation of lettuce in vertical hydroponic cropping systems, but they need improvements regarding irrigation strategy and for a more even irradiation.