PRACTICE & CASES · FROM THE GREENHOUSE
Every case below comes from the daily monitoring of a live crop: what the sensors measured, the advice that followed, and what happened next. Including the days when it could have gone better.
What you are looking at
Seven practical cases in tomato and cucumber, with the original sap flow and stem diameter charts. They all show the same thing: together, those two signals reveal whether a climate or irrigation action pushes the plant vegetative or generative — often within a few hours, and always before you can see it on the crop.
In the charts, the solid line is the measurement and the dotted line the forecast. The model is trained on the grower's own data and greenhouse conditions.
Answer block — short and factual, written to be quoted by AI search engines.
CASE 01 · TOMATO · IRRIGATION CONTROL
Sap flow (blue) and stem diameter (green) · 8–11 June 2024 · green area is turgor, red area is stress
Changeable weather makes it hard to keep a steady plant and a good balance. On 8 June it was grey all day. After sunrise the diameter started to drop as transpiration increased and the plant drew on its internal water reserves — a sign of stress. Irrigation started early, the roots delivered water and the plant refilled those reserves. During the day the water supply exceeded demand, with a vegetative effect. That could have been avoided by delaying irrigation and lowering the volume.
The next day was far sunnier, with higher sap flow. Irrigation was still slightly too early — a cautious choice — which let the plant recover briefly before transpiration exceeded supply and stress set in: a generative effect. Irrigation was stopped late and the diameter increased sharply that night, pointing to less dehydration.
10 June was dark, with hardly any sap flow before 11:00. Irrigation started anyway, while the plant did not need water yet — resulting in swelling, a risk of guttation and a strongly unwanted vegetative effect.
The heart of it: the clock tells you when you usually irrigate. Sap flow tells you when your plant is ready for it.
CASE 02 · TOMATO · CLIMATE ACTIONS
Solid line is measured, dotted line is forecast
The grey weather meant a vegetative pattern was expected. The grower allowed more dehydration the previous night, which produced a deeper drop in diameter — a generative effect. When irrigation started just after 9:00, the plant swelled strongly, exactly as forecast.
At 17:30 the vents closed fully and the humidity deficit dropped. Transpiration then falls and the plant stores water, increasing the diameter: a vegetative effect. The fact that this grower usually keeps a higher humidity deficit in the evening explains the gap between the forecast and the observed diameter.
What this gives you: you follow the effect of a climate action in the very curve in which you took it, instead of guessing at it days later.
CASE 03 · TOMATO · DRAIN & FRUIT QUALITY
8–9 September · low plant activity and rising EC
On 8 September the plant reacted strongly to the start of irrigation, with swelling and a vegetative plant during the day. Irrigation was stopped early and a high humidity deficit was maintained in the afternoon to reduce the overpressure in the plant.
The next morning — grey weather, low plant activity, well forecast — the grower rightly delayed the start of irrigation. But the EC had risen because of a low drain percentage the day before, making the response to irrigation more intense and increasing the swelling. That raises the risk of cracked fruit in sensitive varieties. Irrigation was stopped early again, just a little too early — leading to more substrate drying and shrinkage. At 4:30 an early irrigation followed to compensate.
Why this matters: yesterday's drain percentage decides how your plant responds to today's first irrigation.
Same case across a full week — the control pattern repeats
Plotted across several days it becomes clear that this was not one unlucky day but a recurring pattern. That is exactly what makes it steerable: you know what happens tomorrow if you change nothing today.
CASE 04 · CUCUMBER · FORECAST
Growth plus stress — a strong, generative plant expected
A 48-hour forecast of sap flow and diameter shows the expected plant behaviour based on the current climate control and the expected outside weather. The model is trained on the grower's own data and greenhouse conditions and reaches over 95% accuracy for sap flow and over 70% for diameter.
This grower had recently started using supplementary light in the morning to raise sap flow activity, aiming for a maximally generative and productive plant with minimal risk of insufficient recovery, shrinkage and flower abortion. With the current climate and the current activity, a strongly generative plant is expected, with growth in diameter and sufficient recovery.
The confirmation: the forecast told this grower that his new strategy was doing exactly what he had hoped.
Steering the humidity deficit to limit abortion
Using the humidity deficit deliberately to limit flower abortion and ripen the fruit more evenly — with plant activity as the guide instead of gut feeling.
CASE 05 · FRENCH CUSTOMER CASE WITH PAM · THREE VARIETIES
From late February to 23 March 2026 we followed three tomato varieties in the same crop with diameter sensors. Each variety swelled differently, recovered differently and grew differently.
Joannax XR · the diameter drops before the first irrigation, in line with generative control
In Joannax XR the diameter drops before the first irrigation — which fits a generative strategy. But a slight swelling appears before midday, indicating that the build-up towards drain is slower than desired. The advice was therefore not to lower the drain, but to delay it.
DulcizBaby · clearly less swelling than Joannax on 22/03 — a more favourable signal
On 9 March DulcizBaby showed a healthy course with the plant in balance, and on 22 March it swelled clearly less than Joannax. For this variety the advice was simple: keep the current strategy.
Greenhouse 1 · Joannax XR
Compartment 5 · DulcizBaby
Compartment 7 · Beefsteak
What we could not explain
In Joannax XR the higher activity could not be explained with our radiation data. That is how it reads in the report and that is how we leave it — a point to follow up, not a conclusion to polish away.
DATA QUALITY · WHY YOU CAN TRUST THESE CURVES
Sensors on a living plant sometimes take a knock: a clip shifts, a leaf presses against it. That can never be avoided entirely. What can be done is to filter it out — and to show that you filtered it out.
With the FireFly system we measure the same object four or eight times, where that used to be one or two measurements.
A clip that temporarily returns poorer data is excluded from the aggregate. You can see that in the chart from the red dots.
Today this is done manually: every morning an agronomist reviews all the data.
On chrysanthemum, stem clips at a Dutch grower delivered several weeks of uninterrupted data, with no shifting.
The Monitor package measures one plant. That gives you a clear insight into what is happening in your crop and why your plant responds the way it does — and the cases above show how much that reveals. If you also want to actively steer on it, one measuring point alone makes that harder: then you are better off looking at several measuring points per compartment. We would rather say that now than afterwards.
HONEST · WHAT YOU WILL AND WILL NOT FIND HERE
FREQUENTLY ASKED QUESTIONS
How accurate is the 48-hour forecast?
The model is trained on the grower's own data and specific greenhouse conditions. It reaches over 95% accuracy for sap flow and over 70% for stem diameter.
Can I steer my crop on the basis of one measured plant?
One measured plant gives you insight: you see why your crop responds the way it does. Actively steering on a single measuring point is harder, because you cannot tell whether you are measuring an exception or the average. For steering we therefore work with several measuring points per compartment.
What do the colours in the charts mean?
The blue line is sap flow, the green line the stem diameter. A green area points to turgor, a red area to stress. A solid line is measured, a dotted line is forecast.
Does this also work on more difficult crops such as chrysanthemum?
Yes. With stem clips, several weeks of uninterrupted data were collected at a Dutch chrysanthemum grower. Placing the clips takes more care there, and we work that out together with the grower.
What if a sensor takes a knock?
It happens and it can never be avoided entirely. Because we measure the same object four to eight times, deviating clips can be excluded from the aggregate. They are marked in the chart as red dots.
Real-time insight into plant activity, plant balance and irrigation — with concrete daily advice. In 30 minutes we put your growing question next to data from a comparable greenhouse.
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