# Hydroponics

> Hydroponics is growing plants without soil, feeding roots a complete mineral nutrient solution either directly in water or through an inert medium.

- Canonical: https://genetixbay.com/knowledge/glossary/hydroponics.html
- Also written: hydro, hydroponic, hydroponic growing, water culture, hydroponically
- 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"

Hydroponics is the cultivation of plants with their roots in a nutrient solution rather than soil. All mineral nutrients come from dissolved salts. Roots sit either directly in water ([deep water culture](https://genetixbay.com/knowledge/glossary/dwc.md), NFT, aeroponics) or in an inert support medium such as rockwool, [clay pebbles](https://genetixbay.com/knowledge/glossary/clay-pebbles.md) or [coco](https://genetixbay.com/knowledge/glossary/coco-coir.md) that holds little or no nutrition of its own.

## In practice

Because the grower supplies every element, hydro gives fast growth and precise control, and mistakes show quickly. The key numbers to manage are [EC](https://genetixbay.com/knowledge/glossary/ec.md) (often about 1.0-2.4 mS/cm depending on stage), pH (about 5.5-6.5), solution temperature (about 18-22 °C, 64-72 °F) and dissolved oxygen. Systems are either [recirculating](https://genetixbay.com/knowledge/glossary/recirculating-system.md) (solution returns to a reservoir) or [drain-to-waste](https://genetixbay.com/knowledge/glossary/drain-to-waste.md) (each feed is used once).

Many growers count coco and rockwool [fertigation](https://genetixbay.com/knowledge/glossary/fertigation.md) as hydroponics; purists reserve the word for systems with roots in water.

## Don't confuse with

- **Soilless**: any medium without mineral soil, including peat mixes; not always fed like hydro.
- **Aquaponics**: hydroponics fed by fish waste via a bacterial biofilter.

## Myth check

House position: a well-grown hydro run gives a well-grown living-soil run a run for its money, even on taste. Plants mostly don't care where ions come from. Whether soil biology adds something extra is an open question for a blind [Bay Trial](https://genetixbay.com/knowledge/glossary/bay-trials.md).

## Related terms

[Soilless](https://genetixbay.com/knowledge/glossary/soilless.md), [DWC](https://genetixbay.com/knowledge/glossary/dwc.md), [NFT](https://genetixbay.com/knowledge/glossary/nft.md), [Drain-to-waste](https://genetixbay.com/knowledge/glossary/drain-to-waste.md), [Recirculating system](https://genetixbay.com/knowledge/glossary/recirculating-system.md), [Reservoir](https://genetixbay.com/knowledge/glossary/reservoir.md)

## Read more

- [Choosing your growing system: soil, coco, rockwool or hydro](https://genetixbay.com/knowledge/systems/choosing-a-system.md)

## Sources

1. Resh HM, 2022. Hydroponic Food Production, 8th ed. CRC Press. https://doi.org/10.1201/9781003133254
2. 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