The secondary research process involved comprehensive analysis of agricultural databases, peer-reviewed horticultural journals, industry publications, and authoritative agricultural organizations. Key sources included the United States Department of Agriculture (USDA), Food and Agriculture Organization (FAO) of the United Nations, European Commission Directorate-General for Agriculture and Rural Development (DG AGRI), National Agricultural Statistics Service (NASS), International Society for Horticultural Science (ISHS), American Society for Horticultural Science (ASHS), Controlled Environment Agriculture (CEA) Food Safety Coalition, National Greenhouse Manufacturers Association (NGMA), Eurostat Agricultural Statistics, OECD-FAO Agricultural Outlook, and national agricultural ministry reports from key markets.
For hydroponics, aeroponics, soil-based cultivation, aquaponics, glass greenhouses, plastic greenhouses, and net house technologies, these sources were utilized to gather data on greenhouse cultivation, regulatory compliance, technology adoption studies, climatic impact assessments, and market landscape analysis.