Effect of Shading with Various Coloured Films on the Yield and Quality of Celery and Butterhead Lettuce

Abstract: In 2005–2007 at the University of Agriculture in Krakow field experiments with shading with polyethylene films were carried out on medium-early celery ‘Tango’ cultivar and butterhead lettuce ‘Melodion’ cultivar. Shadings with transparent, white and black films made from original and recycled materials were fixed on low tunnel structures on 7 days before harvesting lettuce (from 23.05.2005. and 23.05.2006, respectively) and on 10–12 days before harvesting celery (from 29.06.2005, 1.07.2006 and 25.06.2007, respectively). The best elongation growth of celery was shown under white film which also slightly increased the yield of celery stalks. In relation to yielding of celery in 2005 best effect was obtained under white film, in the next year under transparent and white film and in the last year of the experiment the yield was even in all objects with small advantage under white film. Shading lettuce with transparent film for 7 days before harvest increased the yield and soluble sugars content in plants. With the decrease of PAR permeability through films dry matter, soluble sugars and ascorbic acid content decreased in celery and lettuce. No differences were shown in the growth, quality and yield of celery and lettuce grown under films made from original and recycled materials.