Within the project Fieldlab Vertical Farming, knowledge is generated about the application of indoor farming. After growing tomatoes in the Vertical Farm facilities at Wageningen University & Research, BU Greenhouse Horticulture in Bleiswijk last year, the team choose to cultivate sweet pepper in the high wire cells.
The aim of the experiment is to study the possibilities and challenges of sweet pepper cultivation without sunlight. The chosen varieties are a mix of both blocky and sweet pointed peppers. Researchers with WUR will be screening the different cultivars for their suitability for indoor cultivation in the high wire cells. From this trial, they will be able to create a cultivation protocol for growing sweet pepper varieties in WUR's vertical farm, based on the results of the best performing varieties.
Knowledge about cultivation with LED supplemental lighting is already present. Researchers at Delphy have been running sweet pepper trial cultivation with LED+sun light. These trials are used as a reference for the cultivation and lighting strategy. Delphy is also a partner in the project Fieldlab Vertical Farming and is highly involved in climate control decisions and crop maintenance actions.
Micro and macroclimate
A total of 11 cultivars are grown in the cells. One of these cultivars is present in both cells to check for consistency between the cells. The growth and development of the varieties are closely monitored as well as the climate in the cells. So far, one of the lessons learned is the importance to monitor both micro and macroclimate to control the climate.
This microclimate can be quite different from the macroclimate, considerably higher RH values were found in close proximity of the plant. There have been upwards curling leaves, mis-setting, and edema that might be the result of this high RH. By lowering the RH setpoint of the macroclimate the leaves are improving in general and at first fruit set also improved. At this moment, there is no continuous fruit set, maybe due to a bit too high 24h temperature.
Previous experiments with other crops taught us that higher temperatures are needed than in the greenhouses due to the lack of heat radiation usually delivered by sunlight. Apparently, sweet peppers react differently in an indoor environment compared to other highwire crops previously tested.
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Wageningen University & Research