Does anyone use silica?

[SallyO420]

I was on Reddit and it seems silica is very popular for hydroponics? I never heard of it before. Does anyone use it and what do you think?

[Ray]

The only commonly-grown plants that absolutely require silicon are grasses like rice.

In my experience, there is no benefit to using additives containing it, and one needs to be wary using them, as they are usually based upon potassium silicate, which can raise the pH of the potting medium, which most orchids dislike.

[thefish1337]

I've used silica extensively in orchids and numerous other plants- I've used both potassium silicate and nano-silica. Orchids do benefit from silica but at low consistent doses- it improves orchids health and resilience to stress both abiotic and biotic stresses. Silica also has benefits to the physical properties of the media and mitigates the chemical stress of excess salts.

Potassium silicate needs to be pH'd to slight acidity in order to reliably deliver the soluble silica to the plants and it slowly flocculates out of solution. Nano-silica and monosilisic acid are newer products with less research but are attempting to get around the solubility drawbacks of potassium silicate. Too much silica can be deleterious especially if using some of the newer formulas.

Numerous studies have been performed on orchids with silica nutrition in both production horticultural settings and in micropropagation. Most tend to show benefits but at the right doses.