Soil moisture now reads the root zone, with a deep reserve line

What changed

We have two soil probes in the ground here, one at 20 cm and one at 35 cm. Until this week the soil moisture figure on the site, and the watering advice that hangs off it, came from the deeper one. That was the wrong probe for the job. The 20 cm layer is where seedlings, lettuce, beans and most of the veggie patch actually drink, and on this moment that layer reads 1%. We dug down to control the reading. It is dust. The 35 cm probe sits at 46% in the same spot.

So the verdict has been switched. The headline soil moisture, the gauge and the irrigation schedule now all read the 20 cm probe. The 35 cm probe has not gone anywhere, it now shows as the deep reserve.

Why the deep reserve line matters

A bare “critical, water now” is only half the story on our clay. The topsoil here goes smushy when wet and rock hard when dry, almost like a brick, and it dries out from the top down. A dry surface over a wet reserve means established trees and shrubs with deep roots are still drawing water, while seedlings and shallow crops are not. That is a very different watering job than when both probes are empty.

The new line under the gauge says which of those you are looking at, in plain words. Right now it reads: Surface dry at 20 cm, deep reserve at 35 cm sits at 46% and is holding. Established plants with deep roots are still drawing water, seedlings and shallow crops are not. When the reserve starts to run down the wording changes, and when both are gone it tells you a deep soak is needed.

Where you will see it

• The soil moisture card on the weather hub now says “Soil Moisture @ 20cm”, with a “Deep Reserve @ 35cm” card beside it.
• The soil moisture monitor and the smart irrigation schedule both carry the deep reserve figure and the plain-words line.
• The Garden Buddy insights feed reports the same two depths, so anything reading that feed sees the same picture.

The old “Moisture @ 5cm” card is gone. It never was a 5 cm probe, it was a copy of the deeper reading with the wrong label, and we would rather show fewer numbers than a wrong one. Flood and creek crossing risk still use the 35 cm probe, sicne catchment saturation is a deep-profile question, and they now say so.