How is it possible that SUStee works for all plants and in all types of soils without needing batteries or other sources of energy? Learn everything about the pF-value on which SUStee relies on.

Many people mistakenly believe that there are different watering frequencies for different plants.

Watering timing varies depending on multiple factors, such as temperature, humidity, season or the growth status of a plant, etc. . The environment – not the type of plant – determines the right time for watering.

There is a beneficial soil moisture range shared by all plants.

It is called “available water capacity”, which works as a common denominator for moisture management for all plants, preventing them from root rot and drying up. SUStee helps you water the right way to maintain this beneficial moisture range.

The beneficial moisture range can be rated using what is academically called pF value.

PF-value is a term often used in agricultural colleges and by commercial farmers. The values are measured using a device called a pF meter (pF stands for “potential force”). Adequate plant watering for any plant is ensured when the pF-value range between 1.7 and 2.3 is observed. SUStee is designed to gradually start turning from blue to white at about pF 2.0, the median value of the range, and will turn completely white at about pF 2.3, which is the perfect time for watering.


“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 plant a lot of effort to extract water, which in turn suggests that the soil is rather dry and the plant struggles to extract water.

“Low pF-value” means that the plant can extract water easily, which in turn suggests that the soil is wet and 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: there 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 start changing its colour from white to blue at a pF-value of 2.0, which is the middle value of the “ideal moisture level”. SUStee will turn completely white at a pF-value of 2.3, which is the upper level of the “ideal moisture level” and the perfect moment to water your plants to grow strong and healthy.

How it works


Why SUStee works in all plants?
In which soils can you use SUStee?



SUStee comes in three different sizes and three chic colours so you can choose the perfect option for your potted plant friends.

Choose your size according to the diameter of the pot.

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