Insert SUSTEE into the soil at the base of a potted plant, up to the " Ω " marking.
It will change color from white to blue within 30 minutes after watering.
Blue ⇒ enough water in soil
White ⇒ in need of watering
Everything about the pF-value SUSTEE relies on.
"pF" stands for "potential force" and describes the effort it takes the plants' roots to extract water from the soil.
"High pF-value" means that it takes the plants a lot of effort to extract water, which in turn suggests that the soil is rather dry.
"Low pF-value" means that the plants can extract water easily, which in turn suggests that the soil is wet.
"High pF-value" means that the soil is dry and plants struggle to extract water. A too "Low pF-value" suggests that the plants' roots are submerged in water and unable to breath.
There is a "pF-value" spectrum which is good for all plants. In other words: this is a quantity of water that is suitable for every plant, enabling it to extract water stress free. This is called the "Ideal moisture level ".
SUSTEE is designed to change its color from white to blue at a pF-value of 2.0, which is the middle value of the "ideal moisture level ". This way, the "ideal moisture level " suitable for every plant can be monitored for every type of plant and soil.