It depends mainly on where your plants are located:
Potted plants - indoors or sheltered outdoors (balcony, terrace) The FYTA Beam G1, Beam G2 and Mini are all suitable here. They are inserted into the pot and measure soil moisture and nutrient availability (EC) directly in the substrate. The Beam G1 and Beam G2 also measure light and temperature.
If you also want to measure humidity in the surrounding environment, add a FYTA Sphere to complement your soil sensor. The Sphere measures light, temperature and humidity and can be combined with any FYTA soil sensor.
For a group of plants - multiple pots in one location - we recommend a FYTA Mini for each pot and one FYTA Sphere for the entire group.
Garden plants - beds, lawns, hedges, trees For plants in open ground, we recommend the FYTA Terra. It is more robust, specifically designed for permanent outdoor use, and measures soil moisture, nutrient availability (EC), light and temperature.