Access to sustainable, adaptable, and cost-efficient technologies remains a significant barrier in agricultural research, particularly in controlled-environment systems for plant propagation. This work presents a conceptual design methodology for creating a modular platform architecture that supports the development of a family of functional growth chambers. The platform enables the scalable implementation of hydroponic systems that address experimental needs in diverse agricultural contexts, especially in regions with limited technical and financial resources. The design approach integrates user-centered need analysis, functional modeling based on flow systems (energy, material, and signal), and heuristic-based architectural modularization. Three physical prototypes were developed from the platform: (i) a chamber for mother plant propagation, (ii) a compact system for small-scale cutting experiments, and (iii) a horizontally scalable system for medium-scale cultivation. Each variant incorporates interchangeable modules for lighting, irrigation, environmental control, and sensing. By enabling the reuse and recombination of components, the proposed architecture reduces material waste, accelerates prototyping, and minimizes economic and environmental costs. Furthermore, the approach fosters accessibility and local innovation by empowering research laboratories and educational institutions to adapt and replicate the technology using open and customizable frameworks. The proposed system aligns with the goals of sustainability transitions, offering a replicable and low-cost solution for experimentation and plant propagation in response to global challenges related to food security, water management, and resource efficiency. This work contributes to the development of smart agricultural systems, offering direct social and environmental benefits that support the democratization of controlled-environment technologies and their potential for large-scale impact.