# Potting mix

> Potting mix is a manufactured container medium, usually peat or coco with perlite, lime and starter fertiliser, designed to drain and hold air better than garden soil.

- Canonical: https://genetixbay.com/knowledge/glossary/potting-mix.html
- Also written: potting soil, potting compost, container mix, bagged soil, growing mix
- Glossary category: Systems and media · 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 potting mix is a blended container medium. Most are [soilless](https://genetixbay.com/knowledge/glossary/soilless.md) despite the name "potting soil": a base of peat, coco or composted bark, an aerating component such as [perlite](https://genetixbay.com/knowledge/glossary/perlite.md) or pumice, lime to set the [pH](https://genetixbay.com/knowledge/glossary/ph.md), often a wetting agent, and a starter charge of nutrients. Some add compost, worm castings or slow-release fertiliser. They are designed for containers, where native soil would compact and waterlog.

## In practice

A good cannabis mix [drains](https://genetixbay.com/knowledge/glossary/runoff.md) freely, has visible perlite or bark, smells earthy rather than sour, and is not heavy or sticky. "Lightly amended" mixes feed [seedlings](https://genetixbay.com/knowledge/glossary/seedling.md) and young plants for about two to four weeks before liquid feeding is needed; "hot" mixes rich in [organic nutrients](https://genetixbay.com/knowledge/glossary/organic-fertiliser.md) can burn seedlings. Check the pH is roughly 6.0-7.0. Mixes for seed starting are finer and lower in fertiliser.

Many growers add extra perlite (20-30%) to standard bags to increase [air space](https://genetixbay.com/knowledge/glossary/air-filled-porosity.md).

## Don't confuse with

- **Garden soil**: native mineral soil; poor in containers on its own.
- **Super soil**: a heavily amended organic mix designed to feed through most of the grow.

## Related terms

[Soil](https://genetixbay.com/knowledge/glossary/soil.md), [Peat](https://genetixbay.com/knowledge/glossary/peat.md), [Perlite](https://genetixbay.com/knowledge/glossary/perlite.md), [Soilless](https://genetixbay.com/knowledge/glossary/soilless.md), [Super soil](https://genetixbay.com/knowledge/glossary/super-soil.md)

## Read more

- [Growing in soil (potting mix with bottled feed)](https://genetixbay.com/knowledge/systems/soil.md)

## Sources

1. Raviv M, Lieth JH, Bar-Tal A (eds), 2019. Soilless Culture: Theory and Practice, 2nd ed. Elsevier. https://doi.org/10.1016/C2015-0-01807-5