pH paper and a conductivity meter at the field edge
A meter in the pocket is not a lab, but it beats guessing.
- Field pH paper and an EC meter are checks, not verdicts.
- You must make the paste properly.
- A field kit is a quick check; a number still needs a lab send.
- Soil colour does not replace pH and EC.
- Don’t lime at the maximum from one paper colour; don’t trust a decimal on an uncalibrated meter.
- Soil-to-water ratio: Follow the strip or meter note. Don’t mix it by hand on a whim
- Name what you see before you feed.
- If leaves, roots and the surface disagree, stop.
What you see in the field
Field pH paper and an EC meter are checks, not verdicts. You must make the paste properly.Walk the worst strip and compare a neighbour. Photograph the whole plant, a close-up and the soil surface. If those three do not line up, do not rush a bag. Lab numbers have to match the field.
Tap to enlarge. The caption says what to photograph. Missing field photos are marked as to-be-added.
Why it looks like this
The field looks like this because the root cannot take water or nutrients the usual way. Fix the soil condition first — drainage, salt, acidity, compaction or a salt of fertiliser — then a thin feed. Rates live in the range on this page; confirm with a local station and the label.
Easy to mix up
Looks like “The lab sheet”
A field kit is a quick check; a number still needs a lab send.
Looks like “Guessing from soil colour”
Soil colour does not replace pH and EC.
Do this / don’t do that
- 1Field pH paper and an EC meter are checks, not verdicts. You must make the paste properly.
- 2Soil:water as the note says. Read paper in good light. EC on a saturated paste or as the meter says. Log spot and date. Extremes go to the lab.
- 3Don’t lime at the maximum from one paper colour. Use the range on this page only as a range. Confirm with a local station and the product label.
Don’t do this first
- Don’t lime at the maximum from one paper colour; don’t trust a decimal on an uncalibrated meter.
Rate range
Soil-to-water ratio
Follow the strip or meter note
Don’t mix it by hand on a whim.
Unit
On EC, see whether it is mS or μS
A misread is off by a thousand times.
These are ranges. Confirm with your local extension station and the product label.
When you see Field pH paper and an EC meter are rulers, test. Walk an S and mix — one hole is not the field.
Lesson video
2026-05-21 · Li Zeyu · For learning. Serious damage: local agronomist or a soil test.
For learning only. Fertiliser and pesticide decisions need a local agronomist and a soil test.
Not sure? Photograph the field to identify the problem