What soil sensors tell you

EC: salts and minerals in the soil water

The EC sensor measures electrical conductivity. Dissolved nutrients and salts carry an electrical current, so a higher reading means more of them in the soil water. Readings are corrected for temperature, because conductivity rises by about 2% per degree.

• A rising EC can mean salt build-up, which makes it harder for roots to take up water.
• A sudden drop after heavy rain or irrigation can mean nutrients are washing out.

NPK: nitrogen, phosphorus and potassium

The NPK probe gives an estimate of the three main nutrients, within seconds and without lab samples.

• Nitrogen builds chlorophyll and leaf tissue. It drives colour, density and recovery from wear.
• Phosphorus stores and moves energy in the plant. Young seedlings respond strongly to it, so it matters after renovation and overseeding.
• Potassium helps the plant cope with stress, including cold in winter.

Moisture and temperature

Moisture and root zone temperature sensors show whether the grass has the water and warmth it needs to grow. An infrared sensor measures leaf temperature, so the heaters only run when the grass needs it.

How to use the data

Sensors are best at showing trends: changes from day to day and differences between parts of the pitch. Use them to decide when and where to feed. For exact fertiliser rates, keep checking against your regular lab soil tests.