Nutritional and thermal management in indoor vertical farming systems for tropicalized lettuce seedlings: production, gas exchange, and hormonal metabolism

• Grant number: 24/22687-2
• Support Opportunities: Regular Research Grants
• Start date: September 01, 2025
• End date: February 29, 2028
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Luis Felipe Villani Purquerio
• Grantee: Luis Felipe Villani Purquerio
• Host Institution: Instituto Agronômico (IAC). Agência Paulista de Tecnologia dos Agronegócios (APTA). Campinas , SP, Brazil
• City of the host institution: Campinas
• Associated researchers: Carlos Takeshi Hotta ; Fernando Cesar Sala ; Rafael Vasconcelos Ribeiro ; Susana Maria Pinto de Carvalho
• Associated scholarship(s): 25/20578-4 - Nutritional and thermal management in indoor vertical farming systems for tropicalized lettuce seedlings: production, gas exchange, and hormonal metabolism, BP.DR

Abstract

Lettuce production relies on the transplant of robust, high-quality seedlings, which are predominantly produced in specialized nurseries. Indoor vertical farming systems with artificial lighting represent a promising alternative in this context due to their ability to control environmental variables - such as light and temperature - and potentially shorten the production cycle. Given the accelerated growth enabled by these systems, there is a need to adapt nutrient management, particularly nitrogen (N) and calcium (Ca), to balance the potentially excessive accumulation of N and the structural role of Ca in seedling robustness and quality. In Brazil, tropicalized lettuce cultivars have been improved to, among other traits, tolerate high temperatures (>25 ºC). These cultivars may not require the maintenance of mild temperatures (<25 ºC) using air conditioning when produced in indoor vertical systems, potentially lowering production costs. This project aims to evaluate the effects of different N and Ca concentrations in the nutrient solution and temperature management on the production of tropicalized lettuce seedlings in an indoor vertical system. The study will be conducted in three stages: 1) Optimization of N (60%, 80%, 100%, and 120% of the recommended concentration) and Ca (100%, 120%, 140%, and 160% of the recommended concentration) in the nutrient solution; 2) Assessment of temperature regimes (21, 25, 29, and 33 ºC, under fixed or alternating conditions) to determine the optimal thermal conditions; and 3) Comparison between seedlings produced in the indoor vertical system (under the best conditions identified in the previous stages) and those produced in a commercial nursery, followed by a transplant into an greenhouse. The following characteristics will be evaluated: biometric (fresh and dry biomass, plant length, leaf number, specific leaf area, and shoot-to-root fresh mass ratio), days after sowing to transplant stage (DAS), macro- and micronutrient contents, gas exchange, chlorophyll content, and, in stage 2, hormonal profiling (auxins, gibberellins, salicylic acid and jasmonic acid). (AU)