Greenhouse horticulture is a cornerstone of year-round vegetable production. However, escalating climate change is intensifying abiotic stressors (i.e., elevated temperatures, increased vapor pressure deficits, water shortage, and modified solar radiation), threatening both crop productivity and postharvest performance. This review synthesizes current knowledge on how these climatic shifts impact greenhouse microclimate, pest and disease patterns, energy and water requirements, as well as crop development in the Mediterranean region. This study focuses on three major crops (tomato, cucumber, and sweet pepper), which prevail in the regional protected cultivation sector. Among the climate-induced stressors examined, elevated temperature emerges as the primary environmental constraint on greenhouse productivity. In reality, however, a combination of climate-induced stressors is at play, acting simultaneously and often synergistically. Among crops, cucumber generally displays the highest sensitivity to climate-induced shifts, whereas sweet pepper tends to be the most resilient. Next, adaptive strategies are explored, including precision irrigation, structural retrofitting measures, renewable energy integration, Decision Support Systems, and climate-resilient cultivars. Regional case studies revealed diverse country-specific counteractive innovations. As key elements of inclusive climate adaptation, supportive policy frameworks and a practical agenda of targeted research priorities are outlined. In conclusion, the sustainability of greenhouse horticulture under a changing climate demands integrated, technology-driven, and region-focused approaches.

This review integrates current knowledge on how greenhouse conditions regulate the nutritional quality and shelf life of tomato, cucumber, and sweet pepper. Preharvest environmental factors jointly shape fruit composition, firmness, and storage performance through their control of photosynthesis, assimilate partitioning, and structural stability. Across all variables, light intensity and fruit temperature emerge as the dominant determinants of overall quality and shelf life potential. Relative air humidity (RH), irrigation regime, and nutrient balance primarily affect firmness, water loss, and physiological disorders, while CO₂ enrichment, shading, and mineral or biostimulant inputs exert secondary yet consistent effects. Comparative evaluation shows that tomato is most sensitive to temperature and RH, cucumber to water status and epidermal stress, and sweet pepper to radiation for color and antioxidant development. These distinctions confirm that no single climatic optimization can be universally applied, and management must therefore target species-specific physiological constraints to sustain both nutritional excellence and storage performance. Major knowledge gaps remain, particularly regarding the combined effects of interacting environmental drivers and the integration of physiological responses with postharvest behavior. Future research should adopt multifactorial designs and predictive modeling to support climate-smart greenhouse strategies that optimize quality and storability under variable growing conditions.

Leaf area (LA) and SPAD value (a proxy for chlorophyll content) are two key determinants of seedling quality. This study aimed to develop and validate approaches for the efficient retrieval of these features in order to facilitate both management and screening practices. In cucumber, different models were developed and tested for the accurate estimation of LA at the scale of the individual organ (cotyledon, leaf) by using its linear dimensions (length (L) and width (W)), and of the whole seedling by using the 2D image-extracted projected area (from three different angles: 0°, 45°, and 90°). At either scale, the SPAD value was computed by using image (90°)-based colorimetric features. The estimation of individual organ area was more accurate when using L alone, compared with W alone. By using the two dimensions and specific colorimetric features, the individual organ area (R² ≥ 0.92) and SPAD value (R² of 0.77) were accurately predicted. When considering a single view, the top one (90°) was associated with the highest accuracy in whole-seedling LA estimation, and the side view (0°) with the lowest (R² of 0.88 and 0.73, respectively). Using any combination of two angles, the whole-seedling LA was accurately retrieved (R² ≥ 0.88). When using colorimetric features, a poor estimation of the whole-seedling SPAD value was noted (R² ≤ 0.43). The deployment of artificial neural networks (ANNs) further allowed the estimation of specific organ shape traits, and improved the accuracy of all the aforementioned predictions, including the whole-seedling SPAD value (R² of 0.597). In conclusion, the findings of this study highlight that features readily retrieved from 2D images hold promising potential for improving screening routines within the nursery industry.

Greenhouse cultivation enables year-round vegetable production and high yields through precise environmental regulation. Yet, the same stable microclimate that promotes crop growth also favors the proliferation of pests and diseases. This review synthesizes current knowledge on how greenhouse climate variables govern pest and disease epidemiology in tomato, cucumber, and sweet pepper. Only greenhouse-based studies were included to ensure direct relevance to protected horticulture. Microclimatic stability determines infection probability, vector behavior, and host susceptibility. Warm, humid conditions promote fungal and bacterial pathogens, whereas dry, high vapor pressure deficit (VPD) environments favor mites and thrips and enhance virus transmission. Species-specific traits further modulate vulnerability. Tomato is dominated by virus–bacterium complexes and foliar/stem fungal diseases, cucumber by phytopathogenic fungi favored by high relative humidity (RH) and soilborne pathogens, and sweet pepper by virus–vector systems and long-cycle fungal infections. Temperature exerts the strongest influence, while RH and VPD jointly regulate surface moisture and vector activity. Light intensity and spectral composition also affect pest orientation and fungal sporulation. Integrating environmental sensing, biological control, and adaptive climate regulation offers a pathway toward preventive, climate-smart Integrated Pest Management (IPM). The review highlights the emerging role of climate-informed decision-support systems (DSSs) and the need for greenhouse-specific datasets to improve pest and disease forecasting.

Water loss during storage is a major cause of postharvest quality deterioration in cucumber, yet existing methods to monitor hydration are often destructive or require expensive instrumentation. We developed a low-cost, non-destructive approach for estimating fruit relative water content (RWC) using visible-light color imaging combined with an ensemble machine-learning model (Random Forest). A total of 1200 fruits were greenhouse-grown, harvested at market maturity, and equally divided between optimal and ambient storage temperature (10 and 25 °C, respectively). Digital images were acquired at harvest and at 7 d intervals during storage, and color parameters from four standard color systems (RGB, CMYK, CIELAB, HSV) were extracted separately for the neck, mid, and blossom regions as well as for the whole fruit. During storage, fruit RWC decreased from 100% (fully hydrated condition) to 15.3%, providing a broad dynamic range for assessing color–hydration relationships. Among the 16 color features evaluated, the mean cyan component (μC) of the CMYK space showed the strongest relationship with measured RWC (R² up to 0.70 for whole-fruit averages), reflecting the cyan region’s heightened sensitivity to dehydration-induced changes in pigments, cuticle properties and surface scattering. The Random Forest regression model trained on these features achieved a higher predictive accuracy (R² = 0.89). Predictive accuracy was also consistently higher when μC was calculated over the entire fruit surface rather than for individual anatomical regions, indicating that whole-fruit color information provides a more robust hydration signal than region-specific measurements. Our findings demonstrate that simple visible-range imaging coupled with ensemble learning can provide a cost-effective, non-invasive tool for monitoring postharvest hydration of cucumber fruit, with direct applications in quality control, shelf-life prediction and waste reduction across the fresh-produce supply chain.

Tomato, cucumber, and sweet pepper represent the backbone of greenhouse vegetable cultivation. Over recent decades, developments in agronomic practices have been central to improving yield, resource-use efficiency, resilience to abiotic stresses, and product quality. This review synthesizes dispersed evidence on water and nutrient management, cultivar improvement, grafting, canopy management, biological inputs, and postharvest-oriented agronomy, while highlighting that the three crops exhibit markedly different responses to these practices. These responses are primarily driven by crop-specific differences in source–sink balance, root-zone regulation, canopy architecture, reproductive stability, and postharvest metabolic regulation. Tomato typically demonstrates substantial improvements in yield and water use efficiency under optimized fertigation strategies, with canopy management additionally promoting source–sink balance and stress resilience. Cucumber, by contrast, is particularly sensitive to water deficits, salinity, and nutrient imbalances, necessitating stricter control of irrigation and fertilization to maintain stable root-zone water flux and transpiration dynamics. Sweet pepper often exhibits greater physiological complexity, as yield stability is strongly influenced by microclimate-sensitive metabolic and ionic balance, frequently associated with trade-offs in quality, including firmness, color development, and nutritional composition. The success of grafting, microbial inoculants, and biostimulants further varies considerably among crops, reinforcing the need for crop-specific strategies rather than generalized approaches. Postharvest-oriented agronomy, involving the regulation of nutrient supply, harvest timing, and canopy structure, is becoming increasingly important for prolonging shelf life and improving quality in line with market demands. Sustainability-oriented practices, including nutrient recycling and water-saving strategies, additionally contribute to reducing environmental burdens while maintaining profitability. By identifying species-specific physiological constraints and agronomic priorities, this review highlights that crop-customized and physiologically integrated management strategies are essential for improving productivity, resilience, and quality in protected cultivation.