One of the most powerful features in GrowVPD Pro is the ability to create automation rules that work across every brand you own. An AC Infinity controller can drive its own Cloudline fan from a live VPD reading, a Bluelab Guardian can push a pH drift alert while a Vivosun GrowHub opens a CO2 outlet during the photoperiod, and a simple Tuya smart plug can sit between any temperature sensor and a dumb oil heater for a cold-night safety net. GrowVPD Pro pulls all of it into one dashboard.

Tested on real hardware so far: Tuya / Smart Life plugs, an air conditioner and a Zigbee gateway with its sensors, Mars Hydro lights and iTime timers, and Bluetooth thermo-hygrometers. AC Infinity, Spider Farmer, Vivosun, Bluelab and SANlight are implemented and being verified with growers who own them.

This guide walks you through everything you need to know about setting up automation rules, from basic concepts to advanced configurations.

What Are Automation Rules?

An automation rule is a simple cause-and-effect instruction: when a certain condition is met, perform an action. On Android, GrowVPD Pro checks your rules every 15 minutes in the background using Android's WorkManager, so your automation keeps running even when the app is closed. On iPhone, rules are checked about every 45 seconds while the app is open; in the background iOS only lets the app run now and then, at times iOS chooses.

Each rule consists of three parts:

  1. Sensor input — which device provides the data (temperature, humidity, VPD, CO2, PPFD, soil moisture)
  2. Condition — what threshold triggers the rule (e.g., VPD rises above 1.5 kPa)
  3. Action — what device should do when the condition is triggered, and what it should do when the condition is restored
Key advantage: GrowVPD Pro communicates with each brand’s cloud or controller independently, so one rule can combine a sensor and a target device from different brands (Tuya, AC Infinity, Mars Hydro, Spider Farmer, Vivosun, Bluelab, SANlight). That said, the cleanest, safest rules are usually inside one brand — an AC Infinity controller nudging its own fan, a Vivosun GrowHub opening a Vivosun outlet — because the controller is designed to run that loop. Cross-brand rules shine when you want a simple switch (a Tuya plug) to react to any sensor, or when you want notifications from a sensor that doesn’t have its own actuators (like a Bluelab Pulse).

Creating Your First Automation Rule

Open the Automation tab in GrowVPD Pro. Rules belong to a room or a tent, so create those first if you have not yet. Then either switch on Full Auto, which builds a set of rules for the tent's growth stage from the devices it finds, or add your own rule: Custom Rules on Android, the + button on iPhone. The steps below walk through a custom rule.

Step 1: Select the Sensor Device

Choose which connected device provides the sensor data you want to monitor. This could be a standalone sensor (like a Tuya WiFi sensor) or a controller with built-in sensors (like an AC Infinity Controller 69 Pro). The app will show you which data types each device reports.

Step 2: Choose the Condition Type

Select what you want to monitor. GrowVPD Pro supports these condition types:

Any rule can also be limited to a time window (see Step 7).

Step 3: Set the Threshold Value

Enter the value that should trigger your rule. For example, if you want to activate a fan when VPD exceeds 1.4 kPa, set the threshold to 1.4 with a "greater than" condition.

VPD also supports a range (min and max values). For example, you might want to keep VPD between 1.1 and 1.4 kPa during flowering — choose the out-of-range condition and set the lower value to 1.1 and the upper to 1.4.

Step 4: Set the Hysteresis

Hysteresis is a buffer zone that prevents your devices from rapidly cycling on and off. If your VPD threshold is 1.4 kPa with a hysteresis of 0.1, the rule triggers at 1.4 but does not restore until VPD drops below 1.3. On Android you enter it as the OFF value (here 1.3), the reading at which the device switches off again; on iPhone it is the Hysteresis slider.

Tip: Always set hysteresis. Without it, a sensor reading that fluctuates around your threshold (e.g., 1.39, 1.41, 1.39, 1.41) would cause your device to switch on and off every 15 minutes. A hysteresis of 0.1 kPa for VPD or 2°C for temperature works well for most setups.

Step 5: Select the Target Device

Choose which device should respond when the condition is met. This can be any controllable device in your setup: a smart plug, an exhaust fan, a humidifier, a heater, or a grow light. The device does not need to be from the same brand as your sensor.

Step 6: Define the Actions

Set two actions (or choose Notify instead of a device to get an alert without switching anything):

Step 7: Optional Advanced Settings

On iPhone all of these are under Advanced in the rule editor. On Android the rule editor offers the time window (Advanced › Schedule) and the maximum run time; the app uses a 3-minute minimum on time, a 5-minute minimum off time and a fixed priority, and rules made by Full Auto carry the growth stage they were made for.

Example Automation Rules

AC Infinity: Native VPD Loop

The single cleanest rule in a tent — same brand, built-in probe, controller in charge. Keeps your VPD inside the flowering band without the rule ever leaving AC Infinity’s own hardware loop.

Night Temperature Safety Net (Any Sensor → Tuya Plug → Dumb Heater)

A good cross-brand example. The plug is just a switch — the brains are your real sensor and GrowVPD Pro. Use whichever sensor you already trust.

Vivosun GrowHub: Daytime CO2 Enrichment

Same-brand loop again: Vivosun’s CO2 sensor trips a Vivosun outlet feeding the regulator — but only with lights on, and the valve is closed if CO2 has not started rising within the maximum run time. Dosing CO2 blind is dangerous; this rule is carefully fenced in.

Bluelab Guardian: pH Drift Notification (No Auto-Dose)

pH is a place where we deliberately do not automate the actuator. A bad reading or a stuck dose can hurt plants fast. This rule watches the Guardian and pings you — you stay in the loop for any nutrient correction.

Automated Light Schedule (Mars Hydro / Spider Farmer / Vivosun LEDs)

Run your photoperiod on a stage-aware schedule, with gradual sunrise and sunset dimming so plants aren’t shocked in or out of the day. Lights get this from the schedule in the light’s own control panel rather than from a rule.

Advanced Automation Features

Beyond the simple "if condition then action" rule, GrowVPD Pro layers in several smart features that make automation safer and more accurate. They work automatically in the background.

Sensor fault detection

Rules never act on bad or old data. Physically impossible values (for example exactly 0% or 100% humidity, a typical sign of a wet or failing probe) are ignored, and readings older than 30 minutes are not used. If a sensor stops reporting for an hour, the rules that depend on it are paused and you get a notification; they switch back on by themselves once the sensor delivers fresh readings again.

Deadband: 2-min dwell + 5-min hold

On top of hysteresis, GrowVPD Pro applies a short stability hold: once a reading has settled back inside the target band for 2 minutes, a rule that acted within the last 5 minutes will not switch its device on again. This kills the rapid-cycle problem when a sensor flickers around a threshold and protects your equipment from short on/off bursts.

Leaf temperature offset for VPD

Air temperature is not the same as leaf temperature, and VPD is what the leaf experiences. With strong direct LED light, leaves can sit 1–3°C below ambient air temp due to transpiration cooling; under HPS, they sit 1–2°C above. GrowVPD Pro therefore calculates leaf VPD, assuming by default that the leaf is 2°C below air temperature. You can change this leaf temperature offset on the VPD chart (one setting for the whole app); on Android, automation rules always use the 2°C default. This is the difference between "my chart says 1.0 kPa" and "my plants actually feel 1.0 kPa."

Night offsets (temp, RH, VPD, CO2)

Plants want different conditions during lights-off. Rather than make you create separate day/night rules, GrowVPD Pro shifts the thresholds of temperature, humidity and VPD rules by the night offsets of the growth stage while the lights are off (for example 3°C cooler and 0.3 kPa lower VPD), and CO2 dosing rules hold (see below). Lights-on/lights-off is detected from the tent’s light schedule; without one, the app treats 21:00–06:00 as night.

Emergency override (temp spike + condensation)

Two safety layers work outside normal rule timing:

You get a notification when the tent emergency mode starts and when it ends; it ends once readings have been back in range for 2 minutes.

Auto stage detection (3-signal voting)

GrowVPD Pro can propose a stage transition (Veg → Pre-flower → Flower → Late flower) by combining three signals:

The check runs every 6 hours. When the signals together point clearly to a different stage, you get a notification proposing it, with Confirm and Dismiss. Confirming records the new stage for the grow; a dismissed proposal is not repeated for that grow for 7 days.

Light dimming ramp (sunrise / sunset)

Light schedules can fade a light in and out. You set the sunrise and sunset length in the light’s schedule (the stage presets use 20–45 minutes). Mars Hydro lamps keep the schedule in the lamp, and when the plan has a sunrise GrowVPD Pro switches on the lamp’s own sunrise/sunset simulation, so it keeps running even if the phone is asleep or offline. For other dimmable lights, the app steps the brightness up and down itself.

Night CO2 hold

CO2 enrichment during lights-off is wasteful (plants don’t consume CO2 in the dark) and risky (without strong ventilation, levels build up). GrowVPD Pro automatically holds CO2 dosing rules during lights-off, keeping your CO2 sensor logging but never triggering the dosing valve. CO2 dosing resumes when the lights come on.

Three-point band (target zones)

When a tent is linked to a grow, its card shows target bands for VPD, temperature and humidity: the stage’s minimum, target and maximum, with a needle where the current reading sits. The band is a display — each rule still has one condition and one target device, so “humidifier on below 55%” and “dehumidifier on above 65%” are two rules.

Safety Features

GrowVPD Pro includes several safety mechanisms to protect your grow and your equipment:

Important: Devices that GrowVPD Pro reaches over your local network (such as Tuya devices with local control) keep responding when your internet is down. Devices that can only be reached through their maker’s cloud (such as Mars Hydro, or battery Wi-Fi sensors) need a working internet connection. For mission-critical safety (like maximum temperature cutoffs), consider using your device's built-in safety features as a backup.

Room and Tent Organization

GrowVPD Pro organizes your space in a hierarchy:

  1. Room — your physical growing space (e.g., "Garage", "Spare Bedroom")
  2. Tent — individual grow tents within a room (e.g., "Veg Tent", "Flower Tent")
  3. Devices — assigned to specific tents
  4. Rules — scoped to a tent (or to a whole room), using that tent's sensors and devices

This structure lets you run different automation profiles for each tent. Your vegetative tent might target VPD 0.8–1.0 kPa while your flowering tent targets 1.0–1.4 kPa, each with its own set of rules and devices.

Link a tent to a grow in the Grow Diary (you pick the grow when you create or edit the tent, or with Link to Diary in Full Auto). The tent’s rules then follow that grow’s current stage.

Monitoring and Energy Tracking

After your rules are running, you can monitor their performance in several ways:

If a rule is triggering too frequently, that usually means your hysteresis is too small or your equipment is undersized for the space. The activity timeline and rule history will help you diagnose and refine your setup.