# Wet-dry cycle

> The wet-dry cycle is the alternation between watering a container and letting it dry back, which refreshes oxygen in the root zone between irrigations.

- Canonical: https://genetixbay.com/knowledge/glossary/wet-dry-cycle.html
- Also written: wet/dry cycle, wet dry cycle, wet-dry cycling, letting it dry out, watering cycle
- Glossary category: Cultivation and training · Evidence: Supported
- 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 wet-dry cycle describes how a container moves from saturation after watering, through [drainage](https://genetixbay.com/knowledge/glossary/runoff.md) and plant uptake, to drier conditions before the next watering. As [water leaves](https://genetixbay.com/knowledge/glossary/fan-leaf.md) the pores, air replaces it, and roots get fresh oxygen. Roots also grow towards moisture, so moderate drying encourages them to explore the pot.

## In practice

In soil, the classic advice is to [water to runoff](https://genetixbay.com/knowledge/glossary/watering-to-runoff.md), then wait until the pot is light (often when the top 2-3 cm, about 1 in, is dry) before watering again. Lift the pot to learn its wet and [dry weight](https://genetixbay.com/knowledge/glossary/dry-weight.md). In coco and rockwool, the cycle is shorter and measured as [dryback](https://genetixbay.com/knowledge/glossary/dryback.md), the percentage of [water content](https://genetixbay.com/knowledge/glossary/moisture-content.md) lost between irrigations; crop steering uses the size of that dryback deliberately.

Too wet too often suffocates roots; [too dry](https://genetixbay.com/knowledge/glossary/over-drying.md) wilts the plant. The ideal size of the cycle depends on medium, [pot size](https://genetixbay.com/knowledge/glossary/pot-size.md) and stage.

## Don't confuse with

- **Dryback**: the measured drop in substrate water content in a single cycle; a quantified wet-dry cycle.
- **Drought stress**: deliberate or accidental extended drying.

## Related terms

[Dryback](https://genetixbay.com/knowledge/glossary/dryback.md), [Overwatering](https://genetixbay.com/knowledge/glossary/overwatering.md), [Underwatering](https://genetixbay.com/knowledge/glossary/underwatering.md), [Field capacity](https://genetixbay.com/knowledge/glossary/field-capacity.md), [Crop steering](https://genetixbay.com/knowledge/glossary/crop-steering.md)

## Read more

- [Drooping cannabis: overwatering vs underwatering](https://genetixbay.com/knowledge/diagnosis/drooping-overwatering-vs-underwatering.md)
- [Drain-to-waste drip and crop steering (generative vs vegetative dryback)](https://genetixbay.com/knowledge/systems/drain-to-waste-crop-steering.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
2. Stemeroff J, 2018. Irrigation management strategies for medical cannabis in controlled environments. MSc thesis, University of Guelph. http://hdl.handle.net/10214/12125