# Potassium silicate

> Potassium silicate is a strongly alkaline liquid or powder used to add silicon (and some potassium) to feeds; it goes into the water first, before other nutrients.

- Canonical: https://genetixbay.com/knowledge/glossary/potassium-silicate.html
- Also written: K2SiO3, liquid silica, potassium silicate solution, water glass (potassium)
- 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"

Potassium silicate is a salt of potassium and silicate, sold as a viscous liquid or soluble powder. Analysis varies by product, so read the label for [SiO2](https://genetixbay.com/knowledge/glossary/silica.md) and K2O content. In water it forms [silicic acid](https://genetixbay.com/knowledge/glossary/silicon.md), the form roots absorb. Its solutions are strongly alkaline.

## In practice

Add it to plain water first, stir, then add the other nutrients, then adjust [pH](https://genetixbay.com/knowledge/glossary/ph.md). Adding it to a finished feed, or mixing it with concentrates, can make the silicate polymerise into a gel or precipitate, and it can drag calcium and [micronutrients](https://genetixbay.com/knowledge/glossary/micronutrient.md) out with it. Expect it to raise pH noticeably; dose before the pH-down step. Typical use aims for tens of mg/L (ppm) of Si in the final solution. It also contributes potassium, which counts towards the feed's K total.

## Don't confuse with

- **Silica**: silicon dioxide; the word is used loosely for any silicon supplement.
- **Monosilicic acid products**: [stabilised](https://genetixbay.com/knowledge/glossary/stabilisation.md) silicic acid, a different formulation.
- **Sodium silicate (water glass)**: brings [sodium](https://genetixbay.com/knowledge/glossary/sodium.md), unsuitable for cannabis.

## Related terms

[Silicon](https://genetixbay.com/knowledge/glossary/silicon.md), [Silica](https://genetixbay.com/knowledge/glossary/silica.md), [Potassium](https://genetixbay.com/knowledge/glossary/potassium.md), [Stock solution](https://genetixbay.com/knowledge/glossary/stock-solution.md)

## Read more

- [Silicon (Si) for cannabis: beneficial, not essential, and how to dose it](https://genetixbay.com/knowledge/nutrients/silicon.md)

## Sources

1. Epstein E. 1994. The anomaly of silicon in plant biology. PNAS 91(1):11-17. https://doi.org/10.1073/pnas.91.1.11
2. Guerriero G, Deshmukh R, Sonah H, Sergeant K, Hausman JF, Lentzen E, Valle N, Siddiqui KS, Exley C. 2019. Identification of the aquaporin gene family in Cannabis sativa and evidence for the accumulation of silicon in its tissues. Plant Science 287:110167. https://doi.org/10.1016/j.plantsci.2019.110167