Reaching New Heights: Using Complex Lighting Regimes to Improve the Efficiency of Vertical Farming

By 2050 over two thirds of the global population will be living in urban areas. Vertical farms
offer the opportunity to produce nutritious foods in cities whilst reducing transport costs.
However, vertical farms have significant costs and carbon emissions associated with lighting
and temperature control. These costs can be mitigated by using complex lighting regimes
which alter light quality and intensity in a way that reduces energy input but does not
significantly alter crop growth. I have subjected microgreens which are commonly grown in
vertical farms to complex lighting regimes to investigate their potential application in indoor
farming. In chapter one I have analysed atmospheric data to create a lighting regime which
changes light quality and intensity to realistically mimic a sunrise in York during the spring. I
report that there were no significant impacts to the biomass of kale, but the biomass of radish
was significantly decreased. This demonstrates that lighting regimes which mimic sunrises
could reduce energy costs for some species. I have also subjected microgreens to
transitioning photoperiods and measured their hypocotyl lengths. In microgreens, the order of
photoperiod exposure influenced hypocotyl length for some species, but not others. Finally, I
have developed an experimental design for efficiently optimising light conditions in small
vertical farms, by taking advantage of the heterogeneity of light intensity that occurs at the
plant level in a vertical farm. After measuring light intensity and biomass variation I have
created a mixed effects model which suggests at an overall light intensity range of 300-500
µmol of light, red light intensity negatively impacts microgreen biomass. These findings
suggest ways in which researchers can use complex lighting regimes to improve the efficiency
of vertical farms.