Silica & Silicon Supplements

Silica is not technically an essential nutrient, which is why it is not in most base feeds – and it is still one of the few additives that reliably does something visible. Plants deposit it in their cell walls, and the result is thicker stems, better heat tolerance and branches that hold weight without staking.

What it actually does

• Structural strength. Silica reinforces cell walls. Stems get thicker and stand up under heavy flowers – less need for plant support.
• Heat and drought tolerance. Stronger cell walls lose less water, which matters under high-intensity LEDs.
• Pest and mildew resistance. A tougher leaf surface is physically harder for sucking insects and fungal hyphae to penetrate. Not a substitute for mildew control, but it helps.
• Faster recovery from training, topping and transplant.

Potassium silicate or mono-silicic acid?

Traditional silica products are potassium silicate – effective, but strongly alkaline. Mono-silicic acid products such as Power Si are the newer route: far lower dose, no pH swing, and no precipitation risk.

The mixing rule

Silica goes in the water first, before anything else, and gets stirred in before the base feed. Adding it to a tank that already has calcium in it produces an instant precipitate – visible white sludge – and you lose both. This is the most common silica mistake and it is entirely avoidable.

What we stock

Power Si, Buddhas Tree Solar Green Power, Canna, Mills and Plant Magic silica products. Pair with CalMag (added separately, not together) and a base nutrient.

Silica FAQs

When should I use it?
Throughout veg and into early flower. Most growers taper it off in the last few weeks.

Will it raise my pH?
Potassium silicate will, substantially. Add it first, let it settle, then pH the finished solution. Mono-silicic acid barely moves it.

Is it worth it?
Of the optional additives, it is one of the few where the effect is visible in the plant rather than only in the marketing.

Why buy silica from The Hydro Bros?

We are a hydroponics shop in Croydon and we run these ourselves. Ask us which type suits your feed and we will tell you straight. Discreet UK and European delivery, and excellent customer reviews on Trustpilot.