Silicon Fertilizers: Debunking the ‘mono silicic acid’ myth!

Introduction In hydroponic gardening, silicon fertilizers are gaining traction as essential tools for improving plant strength, disease resistance, and yield. But with bold marketing claims and social media controversies, it can be difficult for growers to know what to trust. Based entirely on expert-led insights from the Hydroponics Daily podcast, this article breaks down the real benefits of silicon, compares major products, and exposes common myths that confuse the market.

What Is Silicon and Why Does It Matter in Hydroponics? While not officially classed as an essential nutrient, silicon plays a powerful role in plant physiology. In many plants, especially grasses and cereals, silicon strengthens cell walls, making them more resistant to environmental stresses and pest attacks. Plants absorb silicon as silicic acid, which is then transported through the xylem to form hard, protective structures called phytoliths. These structures deter herbivores, resist heat and drought stress, and even dull pruning tools due to their microscopic hardness.

In traditional soil-based systems, silicon is often available. But in hydroponics—especially in systems using peat, coco coir, or rockwool—bioavailable silicon is usually absent. That’s why supplementation is so important.

Debunking the Monosilicic Acid Myth A widespread myth in the hydroponics industry is that only products labelled as containing “monosilicic acid” are effective. In reality, NO PRODUCT CONTAINS STABLE, CONCENTRATED MONOSILICIC ACID – it cannot be stored in such concentrations. Instead, all silicon fertilizers rely on polymerized forms that gradually convert into monosilicic acid upon dilution.

Claims of high monosilicic acid concentrations are not chemically realistic. This reveals either marketing confusion or misinterpretation of the science.

Best Practices for Use

• Apply early in the vegetative stage and continue through flowering.
• Do not overdose — high concentrations can increase EC and cause stress.
• Always follow manufacturer dilution guidelines.
• Avoid products with sodium silicate (liquid glass), which can damage roots and increase soil salinity.
• Eutrema’s Sea Silica is a good option for both organic and conventional growers and is registered for use in organics by OF&G.

Conclusion It may not be an essential nutrient by classical definition, but its benefits in hydroponics are clear and measurable. When chosen wisely and applied correctly, silicon fertilizers can protect plants, improve structure, and maximize yields. Ignore the marketing hype—focus on formulation, lab data, and how the product fits your system. Hydroponic growers looking for that next edge would be wise to include silicon in their nutritional strategy.

Article by Dr Russell Sharp

If you would like to keep up to date with subjects just like this, you can listen to both our podcasts! Links can be found bellow:

Hydroponics Daily Podcast: https://open.spotify.com/show/207T7p7fw9sPjINfSjVXW2

Cereal Killers Podcast: https://t.co/eSEbBkTVHl