How do I use the SM150T Soil Moisture Sensor for side insertion into small growing pots?
The SM150T sensors are well suited to this application as their pins are thinner and sharper than those of the Delta-T ML3 Sensor. It is often possible to push the pins through the sides of a pot and into the media.
You need to take great care when doing this to:
- Minimise compression of the soil. A soft container could mean you squash the sides and deform the soil, which then has an altered bulk density, resulting in the volumetric water content reading being changed.
- Minimise movement of the pins inside the container; this can disturb the media, creating air spaces around the pins
If in doubt, pierce the pots before you start (with a small drill, for example).
As an alternative approach for spot-checking, some growers remove the plant, root ball and soil from the pot and then insert the sensor exactly where they want – the sharp pins make this easy. (Once a plant is established, the whole pot contents come out together).