# What are macronutrients and micronutrients?

> Macronutrients are the elements cannabis needs in large amounts: nitrogen, phosphorus and potassium (primary) plus calcium, magnesium and sulfur (secondary), fed at roughly 30-250 mg/L each. Micronutrients are needed in traces, under about 3 mg/L: iron, manganese, zinc, copper, boron, molybdenum, plus chloride and nickel. Carbon, hydrogen and oxygen come from air and water. Silicon is beneficial, not essential.

- Canonical: https://genetixbay.com/knowledge/answers/macro-vs-micronutrients.html
- Topic: Nutrients · Type: Definition
- Evidence: Established · Status: Draft: awaiting expert review
- Full article: [Mobile vs immobile nutrients: reading old vs new leaves](https://genetixbay.com/knowledge/nutrients/mobile-vs-immobile-nutrients.md)
- Also asked as: What are macro and micro nutrients? | Which nutrients does cannabis need? | What are the essential elements for plants? | What are secondary nutrients? | Is silica a nutrient?
- Updated: 2026-10-31 · Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay Knowledge Base (genetixbay.com/knowledge)"

## Short answer

[Macronutrients](https://genetixbay.com/knowledge/glossary/macronutrient.md) are the elements cannabis uses in large amounts: nitrogen, phosphorus and potassium (the primaries) and calcium, magnesium and [sulfur](https://genetixbay.com/knowledge/glossary/sulfur.md) (the secondaries), fed at roughly 30–250 mg/L each. [Micronutrients](https://genetixbay.com/knowledge/glossary/micronutrient.md) are just as essential but needed in traces, under about 3 mg/L: iron, [manganese](https://genetixbay.com/knowledge/glossary/manganese.md), [zinc](https://genetixbay.com/knowledge/glossary/zinc.md), [copper](https://genetixbay.com/knowledge/glossary/copper.md), boron, [molybdenum](https://genetixbay.com/knowledge/glossary/molybdenum.md), [chloride](https://genetixbay.com/knowledge/glossary/chloride-nutrient.md) and nickel. *Established.*

## Why

An element is essential when the plant cannot complete its life cycle without it and nothing else can replace it [1]. That gives 17 for higher plants: carbon, hydrogen and oxygen from air and water, plus 14 mineral elements from the [root zone](https://genetixbay.com/knowledge/glossary/root-zone.md) [1].

Macro and micro describe quantity, not importance. Macronutrients build bulk: nitrogen in proteins and [chlorophyll](https://genetixbay.com/knowledge/glossary/chlorophyll.md), calcium in cell walls, potassium as the main cell solute [1]. Micronutrients mostly run enzymes, so a little goes a long way and too much is toxic.

Cannabis shows a distinct, recognisable [deficiency](https://genetixbay.com/knowledge/glossary/nutrient-deficiency.md) for each element when it is withheld [3], which is why diagnosis starts with knowing the list.

[Beneficial elements](https://genetixbay.com/knowledge/glossary/beneficial-element.md) such as silicon and [sodium](https://genetixbay.com/knowledge/glossary/sodium.md) can help some crops but are not essential [1].

## The numbers

| Group | Elements | Typical cannabis feed (mg/L) [2] |
|---|---|---|
| Primary macro | N, P, K | N 150–200, P 30–60, K 175–250 |
| Secondary macro | Ca, Mg, S | Ca 150–200, Mg 40–70, S 60–120 |
| Micro | Fe, Mn, Zn, Cu, B, Mo | Fe 1.5–3, Mn 0.3–0.8, Zn 0.1–0.5, B 0.2–0.5, Cu 0.03–0.1, Mo 0.01–0.05 |
| Micro (rarely added) | Cl, Ni | Supplied by water and impurities |
| Beneficial | Si, Na | Si 20–50 if used; Na as low as possible |

## What to do

1. Use a complete base feed that lists both macros and micros.
2. Check that calcium and magnesium are covered, especially with [RO](https://genetixbay.com/knowledge/glossary/ro-water.md) or soft water.
3. Never add single micronutrients by guesswork.
4. Diagnose by where symptoms start: old leaves (mobile) or new growth (immobile).

## Common mistakes

- Thinking [NPK](https://genetixbay.com/knowledge/glossary/npk-ratio.md) is the whole feed.
- Adding iron or zinc "just in case" and causing [toxicity](https://genetixbay.com/knowledge/glossary/nutrient-toxicity.md).
- Calling silica essential.
- Ignoring what the water already supplies.

## Related

- Full article: [Mobile vs immobile nutrients](https://genetixbay.com/knowledge/nutrients/mobile-vs-immobile-nutrients.md)
- Articles: [feed by stage](https://genetixbay.com/knowledge/nutrients/feed-by-stage.md)
- Answers: [what NPK means](https://genetixbay.com/knowledge/answers/what-does-npk-mean.md)
- Terms: [macronutrient](https://genetixbay.com/knowledge/glossary/macronutrient.md) · [micronutrient](https://genetixbay.com/knowledge/glossary/micronutrient.md) · [secondary nutrient](https://genetixbay.com/knowledge/glossary/secondary-nutrient.md)

## Follow-up questions

**Which nutrients are mobile and immobile?** In cannabis, the mobile nutrients are nitrogen, phosphorus, potassium and magnesium, plus chloride, nickel and, moderately, molybdenum; their shortages show on old, lower leaves first. The immobile or low-mobility nutrients are calcium, boron, iron, manganese, copper and zinc; their shortages show on new growth. Sulfur is intermediate, often showing mid-canopy and on newer leaves.

**Are micronutrients less important than macronutrients?** No. Micronutrients are needed in tiny amounts but are just as essential: a plant short of iron or boron fails as surely as one short of nitrogen. The difference is dose. A cannabis feed carries iron at about 1.5-3 mg/L and molybdenum at 0.01-0.05 mg/L, against nitrogen at 150-200 mg/L. Overdosing micronutrients is toxic, so never guess.

**Is silica an essential nutrient for cannabis?** Silicon is not an essential nutrient for cannabis; plants complete their life cycle without it, so it is classed as a beneficial element. In many crops it strengthens cell walls and reduces some stresses, and cannabis does take it up, but cannabis-specific evidence for yield or quality gains is thin. Growers commonly add 20-50 mg/L silicon.

## 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
3. Cockson P, Landis H, Smith T, Hicks K, Whipker BE, 2019. Characterization of nutrient disorders of Cannabis sativa. Applied Sciences 9(20):4432. https://doi.org/10.3390/app9204432