<p>The objective of this study was to promote the utilization of non-marketable greenhouse-grown tomatoes, targeting smallholder farmers affected by market price volatility. In the medium term, the goal is for smallholder farmers to locally process tomato-based foods, creating the necessary synergies to influence participatory governance. This approach was applied to the case study of small-scale greenhouse tomato farmers in the northeastern region of the State of Mexico, Mexico. The research used a mixed-methods framework with data collection techniques and systems engineering tools in the context of a greenhouse tomato value chain map in the region of interest. The research consisted of four phases: assessment, identification of factors affecting the post-harvest of greenhouse-grown tomatoes by smallholders and mapping of their value chain, design and development of the intervention (spicy sauce based on dehydrated tomatoes), and knowledge transfer to smallholder farmers for the production of tomato sauce with non-marketable fruits. The results of the assessment showed that agricultural work depends on family organization and crop diversification; almost all smallholder farmers lose tomatoes after harvest; 73% expressed interest in learning how to process them; and most lack training in food processing. Dehydrated salsa varieties were designed, combining tomato types (fresh, roasted, and boiled), grinding methods (molcajete and mill), and spiciness (high, medium, and low). A manual on their preparation process was written and given to the small farmers. Finally, a training workshop was held, focusing on strengthening skills for growing tomatoes in greenhouses and the process of making hot salsa from dehydrated tomatoes. The study results demonstrated that the practical application of an intervention improves food production.</p>