Monk Makes Plant Monitor - Capacitive Moisture Meter with Temperature & Humidity

If you have trouble keeping your plants healthy by avoiding overwatering, the Monk Makes Plant Monitor is an easy and friendly way to get started with sensing and gardening projects with no soldering required.

This garden-stake-shaped PCB gives you capacitive measurement of soil moisture using only one probe, which avoids exposed metal and doesn't introduce DC currents into the soil — preventing corrosion and protecting your plants. In addition to soil moisture, it measures temperature and relative humidity.

• Compatible with BBC micro:bit, Raspberry Pi, Pico, Pico W, and most microcontroller boards, especially those with alligator clip pads.
• Alligator clip rings for easy connection
• Pre-soldered header pins for favorite microcontroller boards
• Easy-to-use UART serial interface
• Additional analog output for soil moisture only
• Built-in RGB LED indicator
• Note: Requires hardware serial/UART support; does not work with SoftwareSerial (e.g., on Arduino IDE devices such as ESP8266)

Technical Resources: Datasheet, Instructions for Raspberry Pi, Pico, micro:bit, and Arduino