Effect of Colored Shade Cloth on the Quality and Yield of Vegetable and Cut Flower in Mississippi

Shade cloth has been used to reduce heat stress at locations with high summer temperature. Depending on plant species, chemical compounds as well morphological characteristics, such as plant height, leaf area, and branching can be altered by shade. The influence of three colored shades (red, blue, and black) with 50% shade and a no-shade control on the growth and yield of two lettuce cultivars (green-leaf ‘Two Star’ and red-leaf ‘New Red Fire’), one snapdragon (Red, Potomac Series, Ball Seed), and one sweet basil cultivar was investigated. Results demonstrated that colored shade cloth increased plant growth indices of lettuce compared to the no-shade control. Red shade cloth resulted in higher leaf area than the black and blue shades and higher lettuce fresh weight than all other three treatments. Lettuce grown under the no-shade control had higher stomatal conductance, possibly in response to the higher photosynthetic active radiation. The two lettuce cultivars varied in their flavonoid compounds, with the green-leaf ‘Two Star’ had higher quercetin glucuronide, quercetin glucoside, and caftaric acid than the red-leaf ‘New Red Fire’, whereas ‘New Red Fire’ had higher concentrations of chlorogenic acid, luteolin, and quercetin malonyl. The shade decreased luteolin and quercetin malonyl concentration for both lettuce cultivars and decreased cyanidin glucoside in the red-leaf ‘New Red Fire’. As for snapdragons, the no-shade control produced the first harvest of flower stems roughly a week earlier than the shade treatments. Shade cloth increased the length of snapdragon flower stems compared to the no-shade control in the first round harvest. In the second round harvest, red shade produced longer flower stems and longer inflorescence of snapdragons than the blue and black shades. Plant growth and yield of basil plants did not vary among shade color.