Innovative energy-saving technology of irradiation of seeds of coniferous trees

The paper presents the results of an effort aimed at creating an innovative energy-saving electrotechnology for irradiation of Thuja Occidentalis seeds by means of eco-friendly UV LEDs. Conifers retain 30 times as much dust as the aspen, 12 times as much as the birch, while their phytoncide production is double that of deciduous plants. Being ever-green, low-maintenance, longer-living, and able to keep their decorative value year round, conifers are a better green-city solution. We have designed two LED UV units. The first unit consists of 54 LEDs and consumes about 2 W, while the second one is a 81-LED, 3-W unit. Over 90% of their emitted light is within the UVA range. Thuja Occidentalis seeds germinate at a 12.8% higher rate when exposed to 2 kJ/m2 UV light as compared to non-exposed controls, making for a faster germination and production of earlier and stronger seedlings. Therefore, pre-sowing UV exposure of seeds is both cost-efficient compared to conventional chemical stimulation, and eco-friendly thanks to zero soil contamination. In terms of technical- and cost-efficiency, using UV LED units have been proven to have 80...90% lower power consumption compared to earlier DRT-400 mercury lamps. UV LED units have been estimated to pay off in approximately four months.