Effect of different lighting under various wavelengths on seed germination inside a vertical farming system

Controlled-environmental agriculture (CEA) refers to innovative agricultural systems that apply precise environmental control, such as humidity, temperature, light and CO₂. The regulation of environmental conditions inside the cultivation area optimizes plant growth and productivity.
Vertical farms (VFs) are CEA systems that use artificial lighting, with specific dimensions, for plant growth and can be designed to operate in different environments, sizes and locations.
VFs take advantage of the vertical orientation and plants grow on shelves, thus multiplying production m^‑2. VFs, with local food production can contribute significantly to the reduction of CO₂ emissions due to food miles elimination.
The most important disadvantage of VF systems is the high energy consumption for lighting.
This study aimed to investigate the effect of five different lighting conditions and three different photoperiods on seed germination in a small-size VF system.
The applied lighting conditions were a) red light, b) blue light, c) far red light, d) red-blue light, and e) a combination of red-blue-far red light.
These light spectra were tested on four different types of seeds: lettuce, cabbage, spinach and arugula.
Seeds were placed in different seedbeds inside the VF and exposed to different lighting conditions and photoperiods for a period of seven days.
The seeds were exposed to light for 12 and 24 h day^‑1 at a distance of 60 cm from the light source and 4 h day^‑1 at 20 cm distance.
Energy consumption was monitored for all lighting treatments.
The purpose was to examine which spectra give higher rates of germination with lower photoperiodic demand and consequently reduced energy consumption.
Results showed that lighting has a great effect on seed germination, while the photoperiod of 4 h can provide satisfactory germination results, with significantly reduced energy consumption.

International Symposium on New Technologies for Sustainable Greenhouse Systems: GreenSys2023

C. Vatistas, D.D. Avgoustaki, T. Bartzanas

vertical farms, control-environmental agriculture, lighting, wavelength, germination, seeds

https://doi.org/10.17660/ActaHortic.2025.1426.29