Gardening and electronics don’t generally go together, and remembering to keep plants watered can be a problem for anyone. Fortunately, there is a solution that combines the two in the form of the SoilWatch 10 capacitive soil moisture sensor.
This device is water and weatherproof, and can be plugged into a potted plant, or even buried under your lawn. As it uses capacitive sensing, there are no exposed metal parts, so it won’t rust like resistive sensors, and it’s relatively immune to temperature changes. The device features a single analog output, allowing it to be used with Arduino boards and other similar microcontrollers with ADC capabilities
Of course, SoilWatch isn’t the only sensing solution on the Tindie indie electronics marketplace. You also may want to consider this I2C Soil moisture sensor by Catnip Electronics. The device works with Arduino, Raspberry Pi, and other systems, and has been reviewed 80 times as of this writing. In fact, it was featured here in 2017 as one of Tindie’s top 5 products, coming it at #2 with over 5000 sold—a number that’s increased significantly since then!