EFFECT OF SUPPLEMENTAL LED LIGHTING ON GROWTH AND QUALITY OF Valerianella locusta L. AND ECONOMIC ASPECTS OF CULTIVATION IN AUTUMN CYCLE

Abstract

New lighting technologies that significantly reduce the energy consumption are in the centre of interest of greenhouse crop producers. In this study, the effect of several LED lights with various spectral composition and high pressure sodium lamp (HPS), as supplemental to solar radiation, on growth and yielding of lamb’s lettuce ‘Nordhollandse’ was tested (in two autumn cultivations). At harvest time, the highest leaf length and area, fresh weight of rosettes and soluble sugars content were obtained under LED lamps that emitted 90% red and 10% blue light. The spectral composition of each kind of LED lamp increased the ascorbic acid content compared to HPS (70% red + 30% blue LED light to the highest extent). Using of LEDs with red and blue diodes reduced the consumption of electricity for V. locusta lighting about 36% to 55% in comparison to HPS. The highest total costs of lamb’s lettuce cultivation was shown under white LEDs.

Keywords

• LED light
• lamb’s lettuce
• growth
• yield
• energy consumption