Short answer: Silicon for plants is a stress-and-structure nutrient. Plants take it up as monosilicic acid, and it helps build stronger cell walls, firmer stems and better tolerance of heat and other stress. Soil and most substrates hold silicon, but usually not in a form roots can absorb. Bionova Silution is a stabilised silicic acid stimulator (1:5000, NPK 0-0-0) that you add to irrigation or spray on the leaves.
Silicon for plants is often misunderstood. It is not a main fertilizer, and it does not replace N, P or K. This guide explains what monosilicic acid is, what Bionova says it does for stems and heat tolerance, and how to use it in your grow. It applies to indoor and outdoor plants, including cannabis.
What is silicon for plants?
Silicon is one of the most common elements in the earth's crust. Most soil is full of it. The problem is that most of this silicon is locked in minerals and sand, where roots cannot reach it.
Plants can only absorb silicon as monosilicic acid. Bionova explains that this is the only form of silicon that is 100% bio-available to the roots, and that most substrates do not contain enough plant-absorbable silicon. This is why a silicon stimulator can make sense even when your soil "contains silicon".
Silution is a bio-stabilised silicic acid, combined with fulvic acid. The stabilising keeps the silicic acid in a usable form in the bottle and in your feed water.
What monosilicic acid does for stems and cell walls
Silicon is built into the plant's tissue. According to the Bionova product information, Silution helps with:
- stronger cell walls and a higher resistance to stress;
- thicker trunks and branches, with more internodes, so branches can carry more weight;
- a stronger defence against plant infections and pests;
- a higher dry weight content of the end product.
The logic is simple. A cell wall with more silicon is harder to damage. A stem that is firmer holds up better when flowers get heavy. This is a support for the plant, not a magic fix: good light, water and feeding still decide the result.
Silicon and heat stress
Heat is where many growers first notice silicon. High temperatures make plants lose water quickly, and weak tissue suffers most. Bionova states that crops fed with Silution are more resistant to temperature differences and extreme temperatures.
The effect is most visible in conditions that are not ideal: greenhouses, indoor grows, warm climates and places with a high risk of infection. If your grow room runs warm in summer, silicon is one of the tools to consider, next to better ventilation and cooling.
For a full heat plan, Bionova offers the Heat Stress Protection Pack. It combines Silution, The Missing Link (a fulvic acid that supports nutrient uptake and lowers stress) and Roots, because strong roots take up more water when temperatures rise.
How to use Silution
These values come from the Silution product page. For your exact plan per substrate, see the feeding charts.
- Start with pure water. Put the water in your tank first.
- Add Silution first. For irrigation, mix 2 ml in 10 litres of water and stir well.
- Then add your other products. Add your main fertilizer and other stimulators and mix again.
- Check pH last. Measure after everything is mixed. Our guide on pH for plants shows the target values.
The order matters. Silicic acid is best added to plain water before other products, and Bionova says to mix thoroughly after each step.
Irrigation or foliar spray?
Both work. Silution can be used from the first week of growth until the final week of flowering, and it is mixable with all Bionova fertilizers, stimulators, minerals, universals and substrates.
- Irrigation: 2 ml per 10 litres, as described above.
- Foliar spray: 2 ml per 1 litre of water. Bionova advises a weekly spray from the start of the growth phase to the end, to promote the number of internodes.
For spraying, a wetting agent helps the liquid spread over the leaf. Bionova Freeflow is a natural yucca-based wetting agent for this.
Mothers, clones and seedlings
Young plants and cuttings sit in humid conditions, where infections spread easily. Bionova's grower tips for these plants:
- Spray clones, seedlings and mother plants every 10 days to strengthen tissue.
- Spray mother plants just before you take cuttings, to strengthen cells and support faster rooting.
Common misunderstandings about silicon
"My soil already has silicon." It does, but mostly in a form plants cannot use. Monosilicic acid is the usable form.
"Silicon replaces my main fertilizer." No. Silution has NPK 0-0-0. It supports the plant; your main fertilizer still provides the nutrients. Bionova also says Silution increases nutrient uptake, so each feed works more efficiently.
"More is better." Stick to the label values. If a value is not on the label or in the feeding chart, do not guess it. Increase or decrease in small steps and watch the plant.
"It fixes heat on its own." It helps the plant cope, but airflow, temperature and humidity must be right. Silicon is one layer of protection, not the only one. For other deficiencies and root-zone issues, see our guides on trace elements for plants and cal-mag for plants.
Which products go well with silicon?
Silicon works best as part of a complete plan: a main fertilizer for your substrate, a healthy root zone and the right pH. If you grow in a living soil, see Living Soil explained. You can find Silution and the other stimulators in the Stimulators collection, and ready-made combinations in the Product Packs collection.
FAQ
What is monosilicic acid?
Monosilicic acid is the form of silicon that plants can absorb through their roots. Bionova Silution contains stabilised silicic acid, so it stays available in your feed water.
How much silicon should I give my plants?
For Bionova Silution, the label advises 2 ml per 10 litres for irrigation and 2 ml per 1 litre for foliar spray. Always check the feeding chart for your substrate.
Can silicon help against heat stress?
Bionova states that Silution makes plants more resistant to temperature differences and extreme temperatures. It supports the plant, but you should still control temperature, airflow and humidity.
Can I mix silicon with other nutrients?
Yes. Silution is mixable with all Bionova fertilizers, stimulators, minerals, universals and substrates. Add it to plain water first, mix well, then add the other products.
