# Slurry test

> A way to measure the pH and EC of a growing medium by mixing a sample with distilled water (often 1 part medium to 2 parts water), letting it stand, and measuring the liquid.

- Canonical: https://genetixbay.com/knowledge/glossary/slurry-test.html
- Also written: 1:2 slurry, 1:2 dilution test, slurry method, medium slurry
- 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"

A slurry test measures root-zone [pH](https://genetixbay.com/knowledge/glossary/ph.md) and [EC](https://genetixbay.com/knowledge/glossary/ec.md) from a sample of the medium itself. In the common 1:2 dilution method, one volume of moist medium is mixed with two volumes of distilled water, left for about 30 minutes, and the liquid measured. Readings depend on the method, so compare like with like (Michigan State University Extension).

## In practice

Use a slurry test when [runoff](https://genetixbay.com/knowledge/glossary/runoff.md) is hard to collect, in [living soil](https://genetixbay.com/knowledge/glossary/living-soil.md), or to check a bag of medium before planting. Take samples from the [root zone](https://genetixbay.com/knowledge/glossary/root-zone.md), not the surface. The 1:2 method gives lower EC numbers than [pour-through](https://genetixbay.com/knowledge/glossary/pour-through.md), so interpret each against its own reference ranges.

## Don't confuse with

- **Pour-through**: measures the liquid pushed out of the pot by added water.
- **Runoff testing**: measures whatever drains after a normal watering, a rougher estimate.

## Related terms

[Pour-through](https://genetixbay.com/knowledge/glossary/pour-through.md), [Runoff EC](https://genetixbay.com/knowledge/glossary/runoff-ec.md), [pH meter](https://genetixbay.com/knowledge/glossary/ph-meter.md), [EC meter](https://genetixbay.com/knowledge/glossary/ec-meter.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)
- [pH and nutrient availability: what pH really controls, by medium](https://genetixbay.com/knowledge/ph-ec/ph-nutrient-availability.md)

## Sources

1. Michigan State University Extension. pHix it! Getting substrate pH just right. https://www.canr.msu.edu/news/phix-it-getting-substrate-ph-just-right
2. 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