Grower Tip
- Add GT Silica to plain water first, rest 15 minutes, then add your nutrient — never the other way around.
- After the second rest, set pH between 5.5 and 6.5. Potassium silicate is strongly alkaline.
- Hydro and semi-hydro: 5mL/L. Potting mix: 2–3mL/L. Wear gloves and eye protection.
- Recirculating tanks: add once a week. Run-to-waste: add each time you mix a fresh batch.
Features
A concentrated mix of silicic acid and potassium hydroxide, made to add silicon to hydroponic nutrient solutions.
Plants deposit silicon in cell walls, which stiffens the wall as a barrier against water loss, fungi and pests.
Labelled analysis is 1.07% silica and 0.58% potassium by weight per volume.
Cannot go into concentrated nutrient stock — it precipitates and becomes unavailable to the plant.
Used through vegetative and flowering, and listed on the GT Coco feed chart at 5mL/L from week 2.
Sold here in 1L, 5.5L and 20L to match small tanks through to large rooms.
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1
Protect yourself
Wear gloves and eye protection. GT Silica is very alkaline and should be kept away from children.
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2
Dose into plain water
Add GT Silica to fresh water at 5mL/L for hydro, or 2–3mL/L for potting mix. Stir well.
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3
Rest the mix
Leave the silica-in-water mix to stand for 15 minutes before adding nutrient.
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4
Add nutrient
Add your base nutrient to that solution, stir thoroughly, and rest another 15 minutes.
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5
Check pH last
Test and adjust pH to 5.5–6.5 after the second rest. Do this after silica, not before.
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6
Repeat on schedule
Recirculating: add once a week. Run-to-waste: add whenever you prepare a fresh nutrient batch.
How much GT Silica do I use?
For hydro and semi-hydro, use 5mL per litre of water. In potting mix, use 2–3mL per litre. On the GT Coco feed chart the rate is 2mL/L in cuttings week 1, then 5mL/L through veg and flower. At 5mL/L, the 1L bottle treats 200 litres of solution, the 5.5L treats 1,100 litres, and the 20L treats 4,000 litres.
When do I add GT Silica — veg, flower, or both?
Use it through vegetative and flowering, including on mature plants. On the GT Coco chart it starts in cuttings week 1 and stays on every week through flower week 8. Recirculating systems get a weekly dose; run-to-waste systems get it whenever you mix a fresh tank. It is an additive, not a complete feed — pair it with a balanced nutrient.
Why can't I pour GT Silica into concentrated nutrient?
Silicon precipitates out of concentrated nutrient solutions and is then unavailable to the plant, so GT Silica is always supplied as a separate additive. Add it to plain water first, rest 15 minutes, then add your nutrient and rest another 15 minutes. Mixing the other way around can cause cloudiness, a pH spike, or lockout. Never add the concentrate straight into a full nutrient tank.
Will GT Silica change my pH?
Yes. Potassium silicate is strongly alkaline and will lift the pH of the tank. Always test and adjust pH after the silica and nutrient have been mixed and have rested, not before. The target band is 5.5–6.5. If pH sits too high, plants cannot take up other minerals properly. Wear gloves and eye protection when handling the concentrate, and keep it away from children.
Which size of GT Silica should I buy?
At the 5mL/L hydro rate, 1L treats 200 litres of solution, the 5.5L treats 1,100 litres, and the 20L treats 4,000 litres. The 1L is the usual starting size for a small tent; 5.5L suits a room that is mixed often; 20L is the bulk option. All three sizes are the same formula — pick by how much solution you mix, not by a different strength.
Can I use GT Silica in potting mix as well as hydro?
Yes. The hydro and semi-hydro rate is 5mL per litre of water; the potting-mix rate is 2–3mL per litre. In both cases add GT Silica to plain water first, rest 15 minutes, add nutrient, rest again, then set pH to 5.5–6.5. It does not replace a complete fertiliser — pair it with a balanced nutrient. It is listed for vegetative, flowering and mature plants.
Description
INTRODUCING GROWTH TECHNOLOGY GT SILICA
Silicon is the second most abundant element in the earths crust making up a component of most rocks.
Plants absorb silicon from silica that has dissolved into the soil water. As you can imagine the concentration of silicon in soil water is not that high because rocks do not tend to be all that soluble.
Silicon concentration in soil water generally does not get above 20 ppm and this is the level we recommend for hydroponic nutrient solutions.
Silicon is a beneficial plant nutrient found in virtually all soils but not, until now, in hydroponic nutrient solutions.
Silicon will strengthen plant cell walls and become a barrier against water loss, fungal infection, particularly mildews, and insect and mite attack.
Silicates are very alkaline and care must be taken with its use. Always check the pH after silicon has been added to the tank.
Handling and Care
- always wear gloves and eye protection
- always store in a locked cupboard
- keep away from children
- dilute with water before adding to tank
- safety data sheets are available
Available in 1 litre, 5.5 litre and 20 litre containers.
What is it exactly?
GT Silicon is a concentrated mixture of silicic acid and potassium hydroxide. This is often referred to as potassium silicate. Its purpose is to add silicon to hydroponic nutrient solutions.
What does it do then?
The effect of silicon comes from the fact that plants deposit silicon in their cell walls and this has the effect of strengthening the cell wall which acts as a barrier between the inside of the plant cell and the environment. The stronger this barrier the better a plant can resist attacks from insects and fungi and also the increased cell wall rigidity gives better tolerance to heat and water stress.
What’s it all about?
Silicon belongs to a class of plant nutrients termed “beneficial nutrients”. These nutrients are not totally essential to the plant but the plant will grow better if it is present. It has even been claimed that the absence of silicon from nutrient solutions constitutes a form of stress to the plant.
OK, how do I use GT Silicon?
Silicon cannot be added directly to concentrated nutrient solutions because it will precipitate from the solution and be unavailable to the plant so it has to be supplied as a separate additive. If GT Silicon is diluted in the nutrient tank at the rate of 1ml per litre of nutrient solution, it will give a concentration of 20ppm silicon, the usual Dutch recommendation.
How often should I dose the tank?
For run to waste systems, add the GT Silicon when making the nutrient solution. For recirculating systems add the GT Silicon to the tank on a weekly basis.
Any precautions?
Yes. GT Silicon is very alkaline. Always check the pH of the nutrient solution after the silicon has been added and correct if necessary. Don’t get it on your skin or clothes. Good practice indicates care should be taken. Keep away from children.
What should I expect if I use GT Silicon?
Silicon provides real benefits to plants, the main one being increased resistance to pathogens.
For use during the vegetative and flowering cycle dilution guide.
FULL STRENGTH 5mL per litre of nutrient solution.
IMPORTANT Always dilute GT SILICA in a seperate container of fresh water before adding to the nutrient solution.
1. Add diluted GT SILICA to the nutrient solution slowly.
2. Mix thoroughly and allow to stand for 15 minutes.
3. Adjust pH between 5.5 and 6.5
RECIRCULATING SYSTEMS
Add GT SILICA once per week
RUN TO WASTE SYSTEMS
Add when preparing the nutrient solution.
SILICA
- Improves nutrient uptake and transportation throughout the plant.
- Increases plant resistance to fungal and insect attack by strengthening cell walls.
- Increases chlorophyll production in the leaves, leading to better photosynthesis.
- Increases the uptake of available C02.
Specifications
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