# What is the best medium for rooting clones?

> There's no single best medium for rooting cannabis clones; the best is the one that stays moist while holding plenty of air. Studies disagree: rockwool rooted best (up to 80%) in one hemp trial, but worst (0% at 9 days) when kept at full water capacity in another, where a 50:50 peat-perlite mix won. Rockwool, peat or coco plugs and aeroponic cloners all work if not waterlogged.

- Canonical: https://genetixbay.com/knowledge/answers/best-medium-for-rooting-clones.html
- Topic: Cloning and mother plants · Type: Comparison
- Evidence: Supported · Status: Draft: awaiting expert review
- Full article: [Clone-only cuts and how to preserve them](https://genetixbay.com/knowledge/breeding/clone-only-preservation.md)
- Also asked as: Rockwool vs plugs for clones | Can I root clones in soil? | Aero cloner vs cubes | Best cloning medium
- Updated: 2026-10-31 · Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay Knowledge Base (genetixbay.com/knowledge)"

## Short answer

The best medium for rooting cannabis clones is one that stays moist but airy. In trials, [rockwool](https://genetixbay.com/knowledge/glossary/rockwool.md) won in one study and lost badly in another, where a 50:50 peat-perlite mix rooted most. Rockwool, [peat](https://genetixbay.com/knowledge/glossary/peat.md) or [coco](https://genetixbay.com/knowledge/glossary/coco-coir.md) plugs and [aeroponic](https://genetixbay.com/knowledge/glossary/aeroponics.md) cloners all work when not [waterlogged](https://genetixbay.com/knowledge/glossary/overwatering.md). *Supported*, with conflicting trials.

## Why

Medium had the biggest effect on rooting in a [hemp](https://genetixbay.com/knowledge/glossary/hemp.md) trial, with success ranging from 13% to 80% across four media; rockwool came out best [1].

A cannabis trial reversed it. After 9 days, peat-perlite rooted 41% of cuttings, coir 29%, peat 16% and rockwool 0%, with all media held at full water capacity; the authors credited peat-perlite's better [air space](https://genetixbay.com/knowledge/glossary/air-filled-porosity.md) and [EC](https://genetixbay.com/knowledge/glossary/ec.md) [2].

Read together, the lesson is water management. In the hemp trial, media were rewetted by hand only when cuttings began to wilt [1]; in the cannabis trial, everything stayed saturated [2], and rockwool, with less air space than the peat-perlite mix, failed.

Aeroponic cloners and water both supply oxygen differently, but warm, wet [root zones](https://genetixbay.com/knowledge/glossary/root-zone.md) invite [Pythium](https://genetixbay.com/knowledge/glossary/pythium.md) and [Fusarium](https://genetixbay.com/knowledge/glossary/fusarium-wilt.md) [3].

## The numbers

| Medium | Trial result | Strength | Weakness |
|---|---|---|---|
| Rockwool cube | Best of 4 in [1]; 0% at 9 days when saturated [2] | Clean, uniform | Easy to drown; start at [pH](https://genetixbay.com/knowledge/glossary/ph.md) ~5.5 |
| Peat-perlite 50:50 | 41% at 9 days, best in [2] | Airy, cheap | Messier; mix your own |
| Coir plug | 29% at 9 days [2] | Airy, reusable stock | Can hold salts; rinse/buffer |
| Peat plug | 16% at 9 days [2] | Cheap, easy | Can stay wet |
| Aeroponic cloner | Not tested in [1][2] | Lots of oxygen | Reservoir hygiene; bare roots |
| Plain water | Not tested | Free | Low oxygen, brittle roots |

**Verdict:** pick the airy option you can keep moist without saturating; the setup and hygiene matter more than the brand of cube.

## What to do

1. Pre-moisten the medium, then squeeze or [drain](https://genetixbay.com/knowledge/glossary/runoff.md) the excess.
2. Lift trays and water only when they lighten.
3. Keep medium at 22–26 °C (72–79 °F).
4. Clean cloner reservoirs between batches.

## Common mistakes

- Sitting cubes in a puddle of water.
- Rich [potting soil](https://genetixbay.com/knowledge/glossary/potting-mix.md) for unrooted cuttings.
- Unbuffered coir with high salts.
- Never cleaning the cloner.

## Related

- Full article: [Clone-only cuts and how to preserve them](https://genetixbay.com/knowledge/breeding/clone-only-preservation.md)
- [Rockwool](https://genetixbay.com/knowledge/systems/rockwool.md) · [Can I root clones in water?](https://genetixbay.com/knowledge/answers/rooting-clones-in-water.md)
- [Do clones need nutrients?](https://genetixbay.com/knowledge/answers/do-clones-need-nutrients.md)
- Terms: [rockwool](https://genetixbay.com/knowledge/glossary/rockwool.md) · [aeroponics](https://genetixbay.com/knowledge/glossary/aeroponics.md)

## Follow-up questions

**Is rockwool good for clones?** Rockwool works well for cannabis clones if you manage its water. In one hemp trial it gave the highest rooting success of four media, but in another cannabis trial, rockwool kept at full water capacity rooted no cuttings within 9 days. Pre-soak it at pH about 5.5, squeeze out excess water, and let it lighten between waterings.

**Can I root clones directly in soil?** Yes. Cannabis clones can root directly in a light, airy mix, such as seedling mix or peat with 30–50% perlite. In one trial a 50:50 peat-perlite mix rooted the most cuttings, ahead of coir, peat and rockwool. Heavy, rich potting soil holds too much water and salts for a rootless cutting. Keep it moist, not wet, and use a dome.

**Is an aeroponic cloner better than plugs?** An aeroponic cloner roots cannabis cuttings in humid air sprayed with water, so oxygen at the stem is excellent and many growers find it fast and even. Its weak points are hygiene and transplanting: warm reservoirs breed Pythium, and bare roots need careful potting. Plugs are slower to set up wrong. Both work; pick the one you will keep clean.

## Sources

1. Campbell SM, Anderson SL, Brym ZT, Pearson BJ, 2021. Evaluation of substrate composition and exogenous hormone application on vegetative propagule rooting success of essential oil hemp (Cannabis sativa L.). PLOS ONE 16(7): e0249160. https://doi.org/10.1371/journal.pone.0249160
2. Hwang SJ, Collado CE, Hwang HS, Yun JH, Hernandez R, 2026. Impacts of commercial and custom substrates on rooting and morphology of Cannabis sativa 'Suver Haze' stem. HortTechnology 36(3):429–434. https://doi.org/10.21273/HORTTECH05810-26
3. Punja ZK, Rodriguez G, 2018. Fusarium and Pythium species infecting roots of hydroponically grown marijuana (Cannabis sativa L.) plants. Canadian Journal of Plant Pathology 40(4):498–513. https://doi.org/10.1080/07060661.2018.1535466