1. Install inactive
The package loads with Climate Control Active turned off, so the fan, humidifier and optional heater are not controlled during initial setup.
Home Assistant VPD climate automation for grow tents
VPD climate control for your Home Assistant grow tent — without building the whole system yourself.
SmartGrowLab is a ready-to-install YAML package for one grow space. Map your existing temperature and humidity sensors and smart switches, then control the exhaust fan, humidifier, optional heater and grow-light schedule from a four-view Home Assistant dashboard.
Install with climate control off, verify the readings and intended actions, then activate the system when you are ready.
€39 one-time · One grow space · One Home Assistant instance
No HACS · No cloud account required by SmartGrowLab
See how Climate Brain works
Plants from my own grow box, Home Assistant dashboard walkthrough and controlled automation demo using test sensors.
Subscribe to @SmartGrowLab ↗ — time-lapses, dashboard previews (Setup, Grow, Settings, Diagnostics), and setup walkthroughs.
Verify the setup before activating climate control
SmartGrowLab installs with climate control off. Map your entities, verify the readings and intended actions, and activate the system only when the behavior looks right.
2. Validate your setup
Confirm that your sensors and switches are mapped correctly, available in Home Assistant and reporting valid states.
3. Observe the decisions
Review temperature, humidity, VPD, Current Targets, System health and Current action without immediately handing over climate control.
4. Activate or roll back
Disable any competing climate automations, activate SmartGrowLab with one toggle, or switch climate control off again if you need to stop the actuators and review the setup.
Built for predictable behavior, not just a VPD number
Calculating VPD is the easy part. Reliable automation also needs clear priorities, device timing, failure handling, phase logic and diagnostics.
🌡️
VPD climate control
Use separate VPD and temperature targets for each growth phase and day or night period. Hysteresis and minimum device ON/OFF times help reduce unnecessary actuator switching.
🧠
One decision engine
Every 15 seconds, Climate Brain resolves safety, VPD and temperature priorities in a defined order, so the package does not issue conflicting commands to the same devices.
🛑
Defined sensor-failure behavior
If no valid temperature or humidity reading remains, SmartGrowLab changes System health to ERROR, switches the humidifier and configured heater off, and falls back to safety ventilation.
📊
Visible system state
See System health, Current action, device availability, active targets, alert flags and runtime information directly in Home Assistant.
🌱
Automatic growth phases
SmartGrowLab can automatically transition from seedling to vegetative for both plant types and from vegetative to flowering for autoflowers. Targets adapt to the active phase and day or night period.
💨
Calculated air exchange
Enter the grow-space dimensions and rated fan airflow to calculate a scheduled cyclic ventilation runtime. Normal fan operation can also satisfy the scheduled air exchange without starting a redundant cycle.
Check your setup before you buy
SmartGrowLab is compatible when Home Assistant exposes your climate readings as sensor.* entities and the controlled devices as switch.* entities. Compatibility depends primarily on the Home Assistant entity domain and availability, not the hardware brand.
Required
- ✓ Home Assistant 2024.10 or newer
- ✓ At least one working temperature
sensor.*entity - ✓ At least one working humidity
sensor.*entity - ✓ Exhaust fan exposed as
switch.* - ✓ Humidifier exposed as
switch.* - ✓ Grow light exposed as
switch.* - ✓ One grow space controlled by this package
Important checks
- — A heater is optional, but must also be exposed as
switch.* - — Second temperature and humidity sensors are optional and recommended for redundancy
- — A
light.*entity cannot be mapped directly - — Cloud-dependent devices may stop responding when internet access is unavailable
- — SmartGrowLab is a software package for Home Assistant, not a physical controller
If your grow light is exposed as light.*, expose it as switch.* through Home Assistant or use a compatible smart plug. Read the full compatible hardware guide →
Built by a Home Assistant grower, for Home Assistant growers
I’m Daniel – a Linux admin and home grower. SmartGrowLab started as my own Home Assistant setup for controlling climate inside my grow tent. The result is a documented, ready-to-use package for growers who want local VPD control without building everything from scratch.
Small, focused, and built for people who understand sensors, switches and local-first automation.
Install in 3 steps
Copy package files
Copy the SmartGrowLab package files into Home Assistant.
Add include lines
Add the package and dashboard include lines to configuration.yaml.
Configure from dashboard
Map your sensors and switches from the SmartGrowLab dashboard.
Uses your existing Home Assistant sensor.* and switch.* entities.
No custom integration. No proprietary controller. No recurring subscription for this purchase.
SmartGrowLab Climate Brain v1.0 — €39 one-time
A ready-to-install Home Assistant package for one grow space and one Home Assistant instance. No recurring subscription for this purchase.
SmartGrowLab Climate Brain v1.0
€39 one-time
A ready-to-install Home Assistant package for one grow space and one Home Assistant instance.
Included- Ready-to-install YAML package with a four-view Home Assistant dashboard
- VPD- and temperature-based control for the exhaust fan, humidifier and optional heater
- Independent grow-light schedule and calculated cyclic air exchange
- Mapping validation, sensor-failure handling and critical safety overrides
- Minimum device ON/OFF times and heater runtime protection
- Installation, testing, troubleshooting and rollback guide
- Best-effort email support and a license for one Home Assistant instance
You are purchasing the current v1.0 package. Maintenance fixes, documentation updates and compatibility improvements may be released on a best-effort basis; future modules and major versions are not included unless explicitly stated.
Not included- Watering, irrigation or nutrient dosing
- CO₂ control, PPFD or DLI measurement
- Multi-zone or multi-tent control
- Custom integrations or general Home Assistant, hardware and electrical troubleshooting
Digital Home Assistant package · One HA instance · Delivered through Gumroad
Choose the approach that fits your setup
SmartGrowLab is designed for one grow space already connected to Home Assistant. Building your own automation and using a dedicated controller are also valid options, depending on how much control, setup work and vendor integration you prefer.
DIY Home Assistant automation
Time investment
- Typically several evenings of building, testing edge cases and debugging
- Full control over the logic and hardware
- Can include VPD control and advanced safety features
- You design and test action priorities and device timing
- You build the dashboard and diagnostics
- You define sensor-failure and restart behavior
- You maintain the system as Home Assistant and your hardware change
SmartGrowLab Climate Brain
€39 one-time
- Ready-to-install Home Assistant YAML package
- VPD- and temperature-based climate control
- Mapping validation and defined failure behavior
- Four-view dashboard and diagnostics
- Documented passive rollout and rollback procedure
- Built for one grow space and one Home Assistant instance
Dedicated hardware controller
Varies by vendor
- Physical controller with a vendor-supported hardware ecosystem
- May include a built-in display or dedicated app
- Supported sensors and devices depend on the selected product
- Customization options vary by vendor
- Home Assistant integration varies
- Cloud or vendor-app requirements depend on the selected controller
Guides & tools
Explore free resources to understand VPD, ventilation and hardware compatibility before you automate the tent.
VPD Calculator
Calculate vapor pressure deficit for seedling, veg and flower.
Open →Air Exchange Calculator
Estimate fan runtime from tent size and airflow.
Open →Hardware Guide
Sensors, smart plugs and local-first setup.
Read →VPD Guide
Deep dive into VPD and Home Assistant automation.
Read →ESP32 + SHT40 sensor setup
Build a dual-sensor ESPHome node for Home Assistant.
Read →What you need
FAQ
Is this a physical controller?
No. SmartGrowLab Climate Brain is a digital product — a Home Assistant Package (YAML configuration) that runs on your existing HA instance. You use your own sensors and smart plugs.
What does the €39 purchase include?
The purchase includes the current SmartGrowLab Climate Brain v1.0 package, four-view dashboard, user guide and a license for one Home Assistant instance. It is a one-time payment. No recurring subscription for this purchase.
Are future updates included?
You are purchasing the version described on this page. Maintenance fixes, documentation updates and Home Assistant compatibility improvements may be released on a best-effort basis. Future modules, major versions, custom integrations and individual installation work are not included unless explicitly stated.
Does Climate Brain handle ventilation timing?
Yes, if you choose to use cyclic ventilation. You can enter your grow box dimensions and fan airflow; the system calculates a recommended runtime to exchange the full air volume, with a phase multiplier. This is optional — Climate Brain works perfectly on VPD triggers alone if you don't need timed air cycles.
How does automatic phase change work?
You set the grow start date and pick the plant type. For photoperiod plants, Climate Brain only auto-transitions seedling → vegetative; you keep manual control over the switch to flowering (which is driven by your light schedule, not days). For autoflowers, Climate Brain handles both seedling → vegetative and vegetative → flowering automatically. You can turn auto phase change off entirely at any time.
What happens if a sensor fails?
If no valid temperature reading or no valid humidity reading remains, SmartGrowLab changes System health to ERROR, switches the humidifier and configured heater off, and falls back to safety ventilation.
It sends one alert, one reminder after one hour if the condition remains active, and a recovery notification when valid readings return.
When two sensors are configured for the same measurement, losing one can result in a WARNING while the remaining valid sensor keeps the system operating.
Does it need internet to run?
Climate Brain itself runs locally on Home Assistant. Cloud-based devices such as Tuya or Sonoff Cloud may work, but local-first devices such as Shelly, Tasmota, ESPHome or Zigbee are strongly recommended for unattended grows because they continue working without internet.
Can I use just one sensor?
Yes. Map your sensor to Sensor 1 and leave Sensor 2 empty. Climate Brain will use that single reading for all decisions.
Will my hardware work?
Yes, if Home Assistant exposes your climate readings as sensor.* entities and your controlled devices as switch.* entities. Climate Brain is brand-agnostic, but local and reliable devices are recommended for unattended grows. See the full mapping table in the Hardware Guide
ESP32 + SHT40 Sensor Guide.
Can I install SmartGrowLab during an active grow?
Yes, but use the documented passive rollout procedure. Install SmartGrowLab with Climate Control Active off, map your entities, verify the readings and Current action, and only then disable your existing climate automations and activate SmartGrowLab.
Never run two climate-control systems against the same actuators.
What happens during a Home Assistant restart?
Home Assistant preserves the System Active state. If Climate Brain was running before the restart, it resumes immediately when HA comes back up — there is no global wait for sensors. All safety layers (heater watchdog, critical override, cyclic vent guardian, mapping validation) are active from the first decision cycle. If you prefer a cold start, toggle System Active off before the restart.
Is the heater required?
No. The heater is optional and the entire heating logic is gated on whether you map a heater switch. Climate Brain works without one — the dashboard shows "not configured" for the heater throughout the UI.
Is support included?
Best-effort email support is available to verified customers for SmartGrowLab bugs, documented mapping issues and dashboard problems.
General Home Assistant troubleshooting, custom integrations, hardware problems and electrical installation are outside the support scope.
What's NOT included?
Watering automation, PPFD/DLI light measurement, camera or live video, timelapse generation, HACS components, sensor drift detection, and runtime watchdogs for fan or humidifier. These are deliberately scoped out and may be released or added later.
Skip building your grow-tent climate logic from scratch.
Map your existing Home Assistant sensors and switches, verify the readings and intended actions with climate control off, then activate local VPD-based control when your setup is ready.