Multi-State Modeling of Greenhouse Cucumber Yield Dynamics Under Microclimate Effects

Greenhouse decisions often rely on static thresholds, yet crop output switches among microclimate-driven regimes. We frame daily cucumber yield as transitions among three ordered states and fit a continuous-time, covariate-dependent multistate model. Data come from four greenhouse compartments in Volos, Greece (24 lines, 62 days). States are defined once from control tertiles and applied across compartments. Transition intensities depend on within-compartment z-scores of relative humidity (RH), photosynthetically active radiation (PAR) and CO2, plus fixed effects. Results show an inherent upward drift through the medium state, "sticky" low-yield spells unless conditions improve, and short-horizon persistence once high yield is reached. RH and PAR are dominant levers, accelerating upgrades and damping regressions; day-to-day CO2 deviations show no clear pooled signal. Residual differences between compartments are modest. By mapping intensities to 7--30 day probabilities, the model yields actionable guidance for humidity and lighting and a lightweight, interpretable component for greenhouse digital twins.