CFD-guided ventilation design to suppress pathogen spread in a cucumber greenhouse

• CFD models ventilation-driven climate and fungal spore dispersion in greenhouses. • Hybrid ventilation (full/bottom vent alternation) suppresses spore transfer. • Taller canopies (1.8 m) suppress near-ground spore spread. Ventilation strategies critically regulate thermal dynamics and pathogen dispersion in solar greenhouses. This study integrates in-situ monitoring and CFD simulations to analyze how natural ventilation modes and crop height jointly govern airflow patterns, temperature distribution, and Corynespora cassiicola spore dispersion in cucumber greenhouses. Through multi-scenario simulations validated by field measurements, we quantified interactions between three ventilation modes (top-only, bottom-only, fully open), crop heights (1.0 m vs. 1.8 m), and wind speeds (1–3 m/s). Key findings reveal that fully open vents achieved maximum cooling (ΔT=13.2°C under 3.0 m/s wind speed and 1.0 m crop height), while taller crops (1.8 m) reduced cooling efficiency. Ventilation modes determined spore pathways: closed/top-only vents restricted longitudinal spread, whereas full/bottom-open configurations enabled vertical escape and cross-facility transmission. The proposed hybrid ventilation strategy—alternating full and bottom openings—achieves dual benefits: effective cooling and pathogen containment through blocked aerial routes. These results establish an operational framework for optimizing greenhouse climate and fungal spore transfer, and shed light on vegetable disease control from empirical practice to predictive science.