Soil Sensors
Air can look fine while the roots are telling a different story.
Verdify’s climate loop watches temperature, humidity, VPD, light, water, and equipment state. The soil probes add a slower, more physical signal: whether the root zone can actually support the demand the air is placing on the plants. They are not just irrigation gadgets. They are the bridge between climate control and plant water stress.
Open the full live soil dashboard
The installed network
Three DFRobot Modbus probes are buried in the greenhouse today. They share the same RS-485 bus as the air probes and report through the ESP32 into the Verdify telemetry pipeline.
| Probe | Hardware | Location | Modbus address | Measures | What it is good for |
|---|---|---|---|---|---|
| South 1 | DFRobot SEN0601 | South floor/pot zone | 7 | Moisture, temperature, EC | Wet baseline, salt/conductivity drift, canna/root-zone context. |
| South 2 | DFRobot SEN0600 | South floor/pot zone | 8 | Moisture, temperature | Second south reference point; shows how uneven the same zone can be. |
| West | DFRobot SEN0600 | West shelf/pot zone | 9 | Moisture, temperature | West-side root-zone heat and drydown, especially under late-day sun. |
Only South 1 measures EC today. That makes conductivity a drift and inspection signal, not a complete nutrient map.
Latest Static Reading
Snapshot from the live database at 2026-05-07 20:55 MDT. The embedded Grafana panels below are live; this table is a static launch snapshot so readers have numbers even if a panel is slow to load.
| Probe | Moisture | Root-zone temp | EC |
|---|---|---|---|
| South 1 | 88.9% | 63.7°F | 76 µS/cm |
| South 2 | 52.4% | 62.8°F | — |
| West | 62.7% | 69.8°F | — |
Same greenhouse. Same evening. Three different root-zone stories.
South 1 is consistently wet. South 2 is much drier even though it lives in the same broad zone. West sits between them for moisture, but its root-zone temperature runs warmer because the west side gets stronger late-day heat and light. That is exactly why a single greenhouse-wide irrigation assumption is too blunt.
What the last week says
Over the last seven days, the probes did not move together:
| Probe | Moisture range | Moisture average | Temperature range | Temperature average |
|---|---|---|---|---|
| South 1 | 85.8–91.9% | 89.2% | 56.5–65.3°F | 61.5°F |
| South 2 | 50.5–63.0% | 54.5% | 55.9–68.2°F | 60.9°F |
| West | 62.3–70.3% | 63.4% | 56.3–83.3°F | 65.8°F |
The story is not “the greenhouse is wet” or “the greenhouse is dry.” The story is spatial. South 1 looks saturated compared with South 2. West does not dry as far, but it heats much harder. That makes West a root-temperature risk on bright afternoons even when its moisture percentage looks acceptable.
Why soil belongs in the climate story
VPD is the drying pressure the air applies to leaves. Soil moisture is the local reserve the plant can draw from. Soil temperature controls how quickly roots can actually move that water.
That creates three important cases:
- High VPD + falling soil moisture — plants are being asked to transpire faster than the root zone is being replenished. Verdify should look at misting posture, irrigation timing, and crop placement before simply raising humidity everywhere.
- Low VPD + very wet soil — disease and root-zone oxygen become the bigger concern. More humidity is the wrong answer even if the leaves look comfortable.
- Moderate moisture + hot root zone — the plant may still be stressed. West can show this pattern because the shelf wall heats after the air has already started to recover.
This is why the soil page exists as its own evidence page. Climate control keeps the air in band. Soil sensing checks whether the plant’s substrate can keep up.
Root-zone temperature
Soil temperature moves slower than air temperature. That lag is useful. It shows how much the pot, media, bench, slab, and irrigation water buffer the crop through hot afternoons and cold nights.
West is the clearest signal right now: over the last week its probe ranged from 56.3°F to 83.3°F, much wider than either south probe. That is a placement story, not just a sensor number.
Conductivity: useful, but narrow
South 1’s SEN0601 also reports EC. Over the last week it ranged from 59 to 83 µS/cm, averaging 69 µS/cm.
That number should not be over-read. It is one probe in one piece of media. EC shifts when fertilizer concentration changes, when the media dries down, when probe contact changes, or when salts accumulate locally. Verdify treats it as a reason to inspect and compare context, not as an automatic fertigation command.
How Verdify uses this signal
Soil data is advisory today. It informs planning and operator triage, but it does not directly override relays, trigger irrigation by itself, or become an automatic nutrient correction.
| Pattern | What it means | Verdify/operator response |
|---|---|---|
| One probe dries down faster than nearby probes | Local media, emitter, crop, or placement difference | Inspect pot/bed, emitter, and plant condition before changing global irrigation. |
| Moisture falls while VPD rises | Air demand is outrunning the root-zone buffer | Review mist/fog posture, irrigation timing, and crop sensitivity. |
| Soil stays saturated during low VPD | Root oxygen and disease risk may matter more than leaf drying stress | Avoid adding humidity blindly; consider ventilation and human inspection. |
| Soil temperature spikes after air temperature recovers | Root-zone heat load persists after the air looks safe | Check shade, airflow, bench placement, and watering time. |
| EC moves sharply | Possible fertilizer change, salt concentration, drying-media artifact, or probe contact issue | Treat as an inspection trigger, not an automatic nutrient correction. |
What comes next
The current three-probe network is enough to prove that the root zone is not uniform. It is not enough to automate every shelf or crop.
Next useful steps:
- add more shelf-level probes where wall drip variability matters most;
- add pH/EC-capable probes in the highest-value soil zones;
- connect soil drydown to irrigation event timing;
- compare root-zone temperature against heat-stress and VPD-stress windows;
- publish soil probe photos so readers can see the physical installation, not just the chart.
Soil sensing connects Growing, Equipment, Zones, Hydroponics, and AI-Writable Tunables. Iris (our OpenClaw AI agent) can change climate and water tactics inside bounded control rules, but the probe data stays evidence-first: measure, compare, inspect, then act.