# Leaf clawing

> Leaves whose tips hook sharply downward like a claw, usually on dark green leaves; a classic sign of excess nitrogen, and also seen with waterlogged roots.

- Canonical: https://genetixbay.com/knowledge/glossary/leaf-clawing.html
- Also written: the claw, claw leaves, clawed leaves, eagle claw
- 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"

Leaf clawing is a downward hooking of the [leaflet](https://genetixbay.com/knowledge/glossary/leaflet.md) tips, so the leaf [looks](https://genetixbay.com/knowledge/glossary/bag-appeal.md) like a bird's claw. On cannabis it is most often linked to excess nitrogen, especially a high [ammonium](https://genetixbay.com/knowledge/glossary/ammonium.md) share, where leaves also turn very dark and glossy; a high ammonium share has been shown to harm cannabis growth and yield (Saloner and Bernstein 2022). The link between the claw shape itself and nitrogen is *Grower practice*.

## In practice

Separate it from [overwatering](https://genetixbay.com/knowledge/glossary/overwatering.md) by lifting the pot: a heavy, wet pot with whole leaves drooping and curling down suggests root oxygen, not nitrogen. Read [runoff](https://genetixbay.com/knowledge/glossary/runoff.md) [EC](https://genetixbay.com/knowledge/glossary/ec.md) and check the feed record. Twisted, glassy, clawed new growth with no other cause points to [broad mites](https://genetixbay.com/knowledge/glossary/broad-mite.md).

## Don't confuse with

- **Overwatering droop**: the whole leaf hangs and curls down, and recovers as the pot dries.
- **Taco leaf**: edges fold up, not down.
- **Praying leaves**: healthy leaves angled upward toward the light.

## Related terms

[Nitrogen](https://genetixbay.com/knowledge/glossary/nitrogen.md), [Overwatering](https://genetixbay.com/knowledge/glossary/overwatering.md), [Nutrient toxicity](https://genetixbay.com/knowledge/glossary/nutrient-toxicity.md), [Ammonium](https://genetixbay.com/knowledge/glossary/ammonium.md)

## Read more

- [Clawing leaves on cannabis: a differential](https://genetixbay.com/knowledge/diagnosis/clawing-leaves.md)
- [Cannabis lookalike problems: how to tell them apart](https://genetixbay.com/knowledge/diagnosis/lookalikes.md)

## Sources

1. Marschner P (ed.). 2012. Marschner's Mineral Nutrition of Higher Plants, 3rd ed. Academic Press. https://doi.org/10.1016/C2009-0-63043-9
2. Saloner A, Bernstein N. 2022. Nitrogen source matters: high NH4/NO3 ratio reduces cannabinoids, terpenoids, and yield in medical cannabis. Frontiers in Plant Science 13:830224. https://doi.org/10.3389/fpls.2022.830224