# Hoagland solution

> Hoagland solution is a classic 1950 hydroponic recipe by Hoagland and Arnon, still used as a research baseline: about 210 ppm N, 31 P, 235 K and 200 Ca.

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- Also written: Hoagland's solution, Hoagland nutrient solution, Hoagland and Arnon solution, half-strength Hoagland
- 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"

Hoagland solution is a complete nutrient solution described by Dennis Hoagland and Daniel Arnon in their 1950 University of California circular, "The water-culture method for growing plants without soil". It is one of the most cited recipes in plant science and is often used at half strength as a research control.

## In practice

Solution 1 uses [calcium nitrate](https://genetixbay.com/knowledge/glossary/calcium-nitrate.md), [potassium nitrate](https://genetixbay.com/knowledge/glossary/potassium-nitrate.md), [monopotassium phosphate](https://genetixbay.com/knowledge/glossary/monopotassium-phosphate.md) and [magnesium sulfate](https://genetixbay.com/knowledge/glossary/magnesium-sulfate.md), plus iron and a [micronutrient](https://genetixbay.com/knowledge/glossary/micronutrient.md) mix. It works out to roughly 210 mg/L (ppm) N, 31 P, 235 K, 200 Ca, 48 Mg and 64 S. Solution 2 replaces part of the [nitrate](https://genetixbay.com/knowledge/glossary/nitrate.md) with ammonium [phosphate](https://genetixbay.com/knowledge/glossary/phosphate.md). For cannabis, it is a sound educational starting point. Most modern cannabis recipes run more phosphorus and magnesium, and replace the original iron source with a modern [chelate](https://genetixbay.com/knowledge/glossary/chelate.md).

## Units and formula

Solution 1 macros in mmol/L: 15 N, 1 P, 6 K, 5 Ca, 2 Mg, 2 S.

## Don't confuse with

- **Commercial "Hoagland" powders**: may differ from the original in micronutrients or iron form.
- **Feed chart**: a product schedule, not a defined recipe.

## Related terms

[ppm of an element](https://genetixbay.com/knowledge/glossary/elemental-ppm.md), [Stock solution](https://genetixbay.com/knowledge/glossary/stock-solution.md), [Calcium nitrate](https://genetixbay.com/knowledge/glossary/calcium-nitrate.md), [Potassium nitrate](https://genetixbay.com/knowledge/glossary/potassium-nitrate.md), [Per-element dosing](https://genetixbay.com/knowledge/glossary/per-element-dosing.md)

## Read more

- [Hydroponic salts explained: what each fertiliser salt supplies](https://genetixbay.com/knowledge/nutrients/hydroponic-salts.md)
- [Building a cannabis feed by stage: ppm targets per element and how to hit them](https://genetixbay.com/knowledge/nutrients/feed-by-stage.md)

## Sources

1. Hoagland DR, Arnon DI. 1950. The water-culture method for growing plants without soil. California Agricultural Experiment Station Circular 347. https://archive.org/details/watercultureme3450hoag/