Pepper is an important specialty crop in the Southwest U.S., cherished for its economic importance, cultural history, and high nutritional values. Despite being a leading pepper producer in the U.S., challenges such as high temperatures, erratic weather patterns, and imports from Mexico have hindered both production and profitability of growers in this region. In response, alternative systems like high tunnels have emerged as viable solutions. The mild winter climate in Southwest Texas offers an ideal setting for winter pepper cultivation in high tunnels, potentially boosting growers' profitability with off-season market opportunities. Application of biostimulants, such as seaweed extracts, holds promise in enhancing cold tolerance and transplant success within high tunnel systems. This study investigates the feasibility of winter pepper production in high tunnels established in the Wintergarden region, assessing various cultivars based on yield and quality. The high tunnel maintained a range of 8-10°C higher temperatures than the open-field on chilly days without additional heating. Seven pepper cultivars were evaluated, with and without seaweed extracts. Seaweed-treated plants exhibited an overall higher stomatal conductance and leaf transpiration rates along with reduced leaf electrolyte leakage. Rio de Oro; a Santa Fe type pepper had the highest PSII efficiency and total fruit yield. Seaweed application also increased total yield and individual fruit weight in cultivar-specific manner. The total phenolic content of fruits was increased by seaweed application at the early maturity stage whereas total flavonoid content varied by cultivar and maturity stage. Despite facing freeze challenges at the early transplant stage, this first-year experiment demonstrated promising potential for off-season pepper production in high tunnels in our region.
