Shade Nets Increase Plant Growth but Not Fruit Yield in Organic Jalapeño Pepper (Capsicum annuum L.)

Colored shade nets have gained attention due to their ability to reduce light intensity and alter the light spectrum, thereby influencing vegetable crop quality and yield. However, limited research has examined their effects on jalapeño pepper (Capsicum annuum L.) growth and yield. This study evaluated the impact of four nets—black, red, silver, and white (40% shade factor)—compared to an unshaded control. The red net altered light quality by increasing the proportion of red and far-red wavelengths, while the other nets reduced light intensity without spectral modification. Although differences in mean air temperature were minimal between shaded and unshaded conditions, root zone temperatures were consistently lower under shade nets. Shade treatments significantly increased plant height, stem diameter, and leaf chlorophyll content relative to the unshaded control. The highest rates of leaf transpiration and stomatal conductance were recorded under unshaded and white net conditions. Net photosynthesis, electron transport rate, intercellular CO2 concentration, or photosynthetic water use efficiency were similar among net treatments. Marketable and total yields did not differ significantly among net treatments in either year; however, in 2021, they were positively associated with light intensity. In conclusion, while colored shade nets promoted vegetative growth, they did not enhance fruit yield relative to unshaded conditions in jalapeño pepper.