# Micronutrient

> A micronutrient is an essential element plants need only in trace amounts, below a few mg/L: iron, manganese, zinc, copper, boron, molybdenum, chlorine and nickel.

- Canonical: https://genetixbay.com/knowledge/glossary/micronutrient.html
- Also written: micronutrients, micros, trace elements, trace minerals, minor nutrients
- Glossary category: Nutrients · 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"

Micronutrients are essential elements required in very small amounts, usually under 0.01% of dry tissue. The accepted list for higher plants is iron (Fe), [manganese](https://genetixbay.com/knowledge/glossary/manganese.md) (Mn), zinc (Zn), [copper](https://genetixbay.com/knowledge/glossary/copper.md) (Cu), [boron](https://genetixbay.com/knowledge/glossary/boron.md) (B), [molybdenum](https://genetixbay.com/knowledge/glossary/molybdenum.md) (Mo), chlorine (Cl) and nickel (Ni). Most work as parts of enzymes or electron carriers, so a shortage halts specific processes rather than general growth.

## In practice

In a hydro feed they are dosed in fractions of a mg/L (ppm) to a few mg/L: iron around 1-3, manganese around 0.5-1, and molybdenum as little as 0.03-0.05. Because the windows between [deficiency](https://genetixbay.com/knowledge/glossary/nutrient-deficiency.md) and [toxicity](https://genetixbay.com/knowledge/glossary/nutrient-toxicity.md) are narrow, especially for boron and copper, growers dose micros from a concentrated stock or premix rather than weighing tiny amounts of salt. [pH](https://genetixbay.com/knowledge/glossary/ph.md) governs micronutrient availability more than anything else: most become less available as pH rises, while molybdenum becomes more available.

## Don't confuse with

- **Beneficial elements**: silicon, sodium, cobalt and selenium help some plants but are not essential.
- **Macronutrient**: needed in hundreds of times larger amounts.
- **Micronised**: a particle size, not a nutrient class.

## Related terms

[Macronutrient](https://genetixbay.com/knowledge/glossary/macronutrient.md), [Chelate](https://genetixbay.com/knowledge/glossary/chelate.md), [Iron](https://genetixbay.com/knowledge/glossary/iron.md), [Boron](https://genetixbay.com/knowledge/glossary/boron.md), [Nutrient toxicity](https://genetixbay.com/knowledge/glossary/nutrient-toxicity.md)

## Read more

- [Building a cannabis feed by stage: ppm targets per element and how to hit them](https://genetixbay.com/knowledge/nutrients/feed-by-stage.md)
- [Iron (Fe) in cannabis: yellow new growth, chelates and pH](https://genetixbay.com/knowledge/nutrients/iron.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. Sonneveld C, Voogt W. 2009. Plant Nutrition of Greenhouse Crops. Springer. https://doi.org/10.1007/978-90-481-2532-6