The climate connection
The instinct on a hot, bright day is to manage the air: push humidity deficit (HD), open vents, run the screens. So we looked at three weeks of a plum-tomato crop and asked a simple question, across days matched for light, what actually tracked biomass?
Not HD. Once you account for temperature, HD's independent link to daily biomass all but disappears in this data. What biomass did track, clearly, was greenhouse temperature (r = 0.77). In this heat, the crop was temperature-driven and HD mattered as a band to stay inside, not a number to maximise. Drier is not automatically better: too low, and transpiration and calcium transport suffer; too high, stomata close and photosynthesis drops.
That's the trap of eyeballing a dashboard: HD and temperature move together on hot days, so it's easy to credit the wrong one. Plant-based measurement is what tells them apart and tells you which lever was actually limiting the crop that day.
From plant data to a setpoint you can use
Insight is worthless if it just sits in a dashboard. The point is to act on it. So the final step is translation: turning what the plant is telling you into a concrete setpoint, the kind you type into your Priva, Ridder or Argus. The HD band to hold. The dryback you're steering toward. The irrigation timing that keeps water balance where the crop wants it, especially as the heat climbs.
That's the difference between reacting to your climate and steering your crop. Measurement on one side, control on the other, finally connected.
