# Foliar feeding

> Foliar feeding is spraying a dilute nutrient solution onto leaves for quick uptake through the leaf surface; it suits micronutrient fixes but cannot replace root feeding.

- Canonical: https://genetixbay.com/knowledge/glossary/foliar-feeding.html
- Also written: foliar feed, foliar spray, foliar application, foliar, spraying leaves
- Glossary category: Nutrients · 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"

Foliar feeding is applying nutrients in dilute solution directly to leaves. Ions enter through the cuticle, [stomata](https://genetixbay.com/knowledge/glossary/stomata.md) and small pores, and are used locally or moved on through the phloem. Uptake works best for elements needed in small amounts, such as iron, [manganese](https://genetixbay.com/knowledge/glossary/manganese.md), zinc, boron and magnesium, and for [urea](https://genetixbay.com/knowledge/glossary/urea.md).

## In practice

Growers use foliar sprays as a quick, temporary fix for a [micronutrient](https://genetixbay.com/knowledge/glossary/micronutrient.md) shortage while correcting the root-zone cause, usually [pH](https://genetixbay.com/knowledge/glossary/ph.md). [Macronutrients](https://genetixbay.com/knowledge/glossary/macronutrient.md) cannot be supplied in meaningful amounts this way: leaves cannot absorb enough without burning. Spray at low strength, with lights off or low, covering leaf undersides, and stop once flowers form. Wet buds invite [bud rot](https://genetixbay.com/knowledge/glossary/botrytis.md), and residues can end up in the harvested flower.

## Don't confuse with

- **Root feeding (fertigation)**: the main route for all nutrients.
- **Foliar pest sprays**: pesticides, a separate topic with their own rules.
- **Misting for humidity**: plain water, no nutrients.

## Myth check

Foliar feeding in flower is not a shortcut to quality, and it adds disease risk. See [botrytis bud rot](https://genetixbay.com/knowledge/diseases/botrytis-bud-rot.md).

## Related terms

[Micronutrient](https://genetixbay.com/knowledge/glossary/micronutrient.md), [Magnesium sulfate](https://genetixbay.com/knowledge/glossary/magnesium-sulfate.md), [Iron chelate](https://genetixbay.com/knowledge/glossary/iron-chelate.md), [Amino acid chelate](https://genetixbay.com/knowledge/glossary/amino-acid-chelate.md), [Urea](https://genetixbay.com/knowledge/glossary/urea.md)

## Read more

- [Iron (Fe) in cannabis: yellow new growth, chelates and pH](https://genetixbay.com/knowledge/nutrients/iron.md)
- [Botrytis (bud rot / grey mould) in cannabis](https://genetixbay.com/knowledge/diseases/botrytis-bud-rot.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