# Fan leaf

> A large palmate cannabis leaf with several long leaflets on a long petiole; fan leaves do most of the plant's photosynthesis and carry few trichomes.

- Canonical: https://genetixbay.com/knowledge/glossary/fan-leaf.html
- Also written: fan leaves, fans, water leaves, shade leaves, big leaves
- Glossary category: Plant biology · Evidence: Grower practice
- 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"

Fan leaves are the big, iconic palmate leaves of cannabis: usually five to eleven serrated leaflets radiating from a long [petiole](https://genetixbay.com/knowledge/glossary/petiole.md), growing from the main stem and branches. They are the plant's solar panels, doing most of the [photosynthesis](https://genetixbay.com/knowledge/glossary/photosynthesis.md) and storing [mobile nutrients](https://genetixbay.com/knowledge/glossary/mobile-nutrient.md) that the plant can draw on later in flower. They carry far fewer glandular [trichomes](https://genetixbay.com/knowledge/glossary/trichome.md) than [bracts](https://genetixbay.com/knowledge/glossary/bract.md) and [sugar leaves](https://genetixbay.com/knowledge/glossary/sugar-leaf.md).

## In practice

Fan leaves are central to the [defoliation](https://genetixbay.com/knowledge/glossary/defoliation.md) argument. House approach: "tuck, don't pluck". Maximise leaf surface like a solar farm for the buds, and tuck leaves out of the way of bud sites rather than strip them. Cultivars respond differently: some clones lost most of their fans with no effect or even grew faster, while others suffered. Stripping within reason doesn't seem to hurt yield, but in the founder's experience tucking helps more. It remains an open question for [GenetixBay trials](https://genetixbay.com/knowledge/glossary/bay-trials.md).

Fan leaves are also the main diagnostic surface. Where and how a fan yellows tells you much more than new growth alone.

At harvest, fans are usually removed first; they make poor smoking material.

## Don't confuse with

- **Sugar leaf**: small, resin-coated leaf within the bud.
- **Leaflet**: one blade of a fan leaf.
- **Cotyledon**: the seed leaf of a seedling.

## Related terms

[Sugar leaf](https://genetixbay.com/knowledge/glossary/sugar-leaf.md), [Leaflet](https://genetixbay.com/knowledge/glossary/leaflet.md), [Petiole](https://genetixbay.com/knowledge/glossary/petiole.md), [Photosynthesis](https://genetixbay.com/knowledge/glossary/photosynthesis.md)

## Read more

- [Defoliation and lollipopping: what to remove, when, and the evidence](https://genetixbay.com/knowledge/training/defoliation-lollipopping.md)

## Sources

1. Spitzer-Rimon B, Duchin S, Bernstein N, Kamenetsky R. 2019. Architecture and florogenesis in female Cannabis sativa plants. Frontiers in Plant Science 10:350. https://doi.org/10.3389/fpls.2019.00350