Influence of Plastic Film Covering Plant Colored on Growth Quality and Yield of Lettuces

Abstract

The greenhouse cover plastic film is one of the most important factors in plant growth in the greenhouse. Therefore, the selection of the type of plastic film has an impact on plant growth and yield. The objective of this experiment was to study the influence of different types of plastic film on the growth and yield of lettuce. The experiment was designed as a split plot in CRD (Completely Randomized Design). Main plot, which was the type of plastic film, consisted of four treatments: red plastic, yellow plastic, white plastic, and an uncovered as a control (Sunlight). Sub plot was the lettuce variety, comprising two varieties: Red Oak and Green Oak. The hydroponic NFT system was used for lettuce cultivation, and data on growth and yield were collected 45 days after sowing. Results indicated significant interactions between plastic film types and lettuce varieties. Green Oak under red plastic exhibited the tallest plants, similar to those under yellow plastic. Red Oak under white plastic showed the widest canopy. Planting Green Oak under white, red, and yellow plastic led to more leaves than uncovered or sunlight conditions. Both Red Oak and Green Oak under yellow plastic had the highest leaf count compared to the sunlight group. White and yellow plastic-covered lettuce had higher SPAD values and leaf color expression (L*, a*, b*) than red plastic. The redness value (a*) of leaves was lowest in the white and yellow plastic groups. Thus, planting lettuce under white and yellow plastic film was most suitable for achieving optimal growth and yield compared to red plastic.