Plant Growth, Yield, and Quality of Containerized Heirloom Chile Pepper Cultivars Affected by Three Types of Biostimulants

Peppers (Capsicum annuum) are one of the most widely cultivated vegetable crops, with per capita consumption of bell and chile peppers being 11.4 and 7.7 pounds in 2017. Biostimulants are an emerging sustainable alternative to enhance plant health by increasing photosynthetic activity, stress tolerance, and nutrient uptake through various modes of action. The effects of different biostimulant applications largely remain unknown in containerized heirloom pepper production. This study evaluated plant growth, yield, and fruit quality of nine heirloom chile pepper cultivars, including ‘Anaheim Chili,’ ‘Ancho or Poblano,’ ‘Big Jim,’ ‘Cayenne Purple,’ ‘Chile de Arbol,’ ‘Jamaica Hot Red,’ ‘Mulato Isleno,’ ‘Padron,’ and ‘Pasilla Bajio’ in a container production system throughout the years of 2020 and 2021. Each cultivar was treated with three types of biostimulants, including Tribus® Original (a mixture of Bacillus bacterias), Vitazyme (containing plant growth regulators and B vitamins), C-Bio CPS (seaweed extract of Ascophyllum Nodosum), and water as control. Pepper cultivars varied in yield and quality, including fruit length, diameter, single fruit weight, and fruit color in both years. ‘Anaheim Chili,’ ‘Big Jim,’ and ‘Jamaica Hot Red’ produced highest marketable yields similarly, with ‘Chile de Arbol’ and ‘Pasilla de Bajio’ producing the lowest marketable yields in both years. Biostimulant application did not affect marketable yield either in 2020 or 2021 but enhanced fruit quality, including fruit length, diameter, and green coloration.