The Growmaster Family – M, L & Prime
Grow Smarter, not Harder.
The three devices work individually or together seamlessly: M measures soil moisture, L monitors climate (Temp/RH), and Prime (P) is your elegant hub with a display that makes everything visible and acts as the central controller.
Growmaster M — Mini Soil Sensor (Soil Moisture)
The compact soil professional for reliable watering: The Growmaster M precisely measures soil moisture and instantly shows you when your plants need water on its integrated web interface—no cloud required.
Highlights
-
Precise soil moisture in % (Soil) – ideal for soil & substrates
-
Integrated web interface (DE/EN/FR), runs locally in the browser
-
Easy initial setup via WLAN-AP (192.168.4.1), mDNS on your home network
-
REST-Endpoints (e.g., /data, /scan, /save, /measure, /restart)
-
Stable & watchdog-friendly, NTP time, lightweight JSON format
Technical Data (compact)
-
WLAN 2.4 GHz • Local Web UI (DE/EN/FR)
-
Measurement: Soil moisture (%), RAW calibration possible
-
Power: USB (5 V) • Local operation – no cloud needed
-
Compatibility: Standalone or with Growmanager App (Free/Pro)
Growmaster L — Climate Sensor (Temperature & Humidity)
The climate guardian for your grow setup: Growmaster L reliably measures temperature & humidity and provides clear live values—either standalone in the browser or connected to Prime/the app.
Highlights
-
Precise temperature & humidity (AHT sensor family)
-
Web interface (DE/EN/FR), local evaluation & JSON-API (/data)
-
WLAN onboarding via AP mode, mDNS accessibility
-
Stable continuous operation, NTP time, watchdog-friendly
-
Perfect partner for Growmaster Prime & Growmanager App
Technical Data (compact)
-
WLAN 2.4 GHz • Local Web UI (DE/EN/FR)
-
Measurements: Temperature (°C), humidity (%)
-
Power: USB (5 V) • Local operation – no cloud needed
-
Compatibility: Standalone, with Prime, or Growmanager App
Growmaster Prime (P) — Display Hub & Control Center
Your stylish control hub: Growmaster Prime shows climate & soil values on a brilliant TFT display, collects data from L and M, logs it, and offers a web API & OTA—everything local, everything under your control.
Highlights
-
2.8" TFT (320x240) with touch – clear donut gauges & soil grid
-
Poll button on the device, event-based fast redraws (fluid UI)
-
Reads multiple L (Temp/RH) & M (Soil) devices on the network (via IP list)
-
Web API (/api/info, /api/data, /api/devices, …), OTA update
-
Logging to SD/internal storage, mDNS, display sleep/night mode
Technical Data (compact)
-
WLAN 2.4 GHz • Touch (XPT2046), TFT (ST7789)
-
Display: Donut gauges (climate) & soil overview, polls every 5 min (configurable)
-
Filesystem: LittleFS (Label spiffs), optional SD logging
-
Power: USB (5 V) • Local web interfaces & OTA
-
Compatibility: Reads Growmaster L/M, works with Growmanager App
System & App
No cloud, full control.
All Growmaster devices run locally on your home network, provide clean JSON data, and can be operated in your browser. With the Growmanager Desktop App (DE/EN/FR), you get a dashboard, history, tasks & more.
-
Free Plan (planned/test): 1x L, up to 3x M, up to 3 plants
-
Pro Plan: extended limits & features
-
Seamless i18n (DE/EN/FR) in firmware & app
Who are M, L & Prime for?
-
Beginners: Ready to start quickly, clear values, no cloud dependency
-
Ambitious Indoor Growers: Stable, expandable, app connectivity
-
Pro-Users: API-driven, logging, OTA, central display with Prime
Why Growmaster?
-
Reliable Measurement: Soil & climate are precise and reproducible
-
Local Data: Privacy by design – everything stays on your network
-
Clean APIs: Easy integration into tools & automations
-
Scalable: Start with M or L – Prime makes it a central hub