# Pour-through

> A standard way to sample root-zone pH and EC: water the pot to saturation, wait 30 minutes to 2 hours, then pour a set volume of distilled water on top and measure the first liquid that drains out.

- Canonical: https://genetixbay.com/knowledge/glossary/pour-through.html
- Also written: pour-through test, pour-through method, pourthru, leachate test
- Glossary category: pH, EC and water · Evidence: Established
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

The pour-through method is an extension-standard way to read the [pH](https://genetixbay.com/knowledge/glossary/ph.md) and [EC](https://genetixbay.com/knowledge/glossary/ec.md) of the solution around the roots without disturbing them. The medium is saturated, allowed to settle, then enough water is poured on to push out about 50 mL of [leachate](https://genetixbay.com/knowledge/glossary/watering-to-runoff.md), which is measured (NC State / NCDA&CS).

## In practice

Do it the same way every time, at the same time after feeding, and track the trend. [Runoff EC](https://genetixbay.com/knowledge/glossary/runoff-ec.md) well above input EC means salts are building up; much lower means the plant is hungry or over-leached. [Runoff](https://genetixbay.com/knowledge/glossary/runoff.md) pH far from input pH means the medium is drifting.

## Don't confuse with

- **Slurry test**: measures a sample of medium mixed with water.
- **Root-zone flush**: heavy watering to wash salts out, not a measurement.

## Related terms

[Slurry test](https://genetixbay.com/knowledge/glossary/slurry-test.md), [Runoff EC](https://genetixbay.com/knowledge/glossary/runoff-ec.md), [Runoff](https://genetixbay.com/knowledge/glossary/runoff.md), [Watering to runoff](https://genetixbay.com/knowledge/glossary/watering-to-runoff.md)

## Read more

- [Runoff testing: how to measure root-zone pH and EC and what the numbers mean](https://genetixbay.com/knowledge/ph-ec/runoff-testing.md)
- [Brown or burnt leaf tips on cannabis: a differential](https://genetixbay.com/knowledge/diagnosis/brown-burnt-tips.md)

## Sources

1. NC State University / NC Department of Agriculture and Consumer Services. The pour-through extraction procedure: a nutrient management tool for nursery crops. https://ncagr.gov/ncsu-pour-through-extraction