Plant Magic - Silicon – Cell Wall Strengthener & Stress Defence for Hydro & Coco
Best for: Growers running hydroponic or coco systems who want stronger stems, better pest resistance, and bigger yields without overcomplicating their feed schedule
Our thoughts
Silicon is one of those additives that actually does what it says on the tin. Plant Magic's Hydro Silicon is properly formulated for recirculating systems, strengthens plants where they need it most, and handles the pH side of things too. One we recommend a lot for growers running heavier crops.
Plant Magic - Silicon is a potassium silicate-based supplement designed to strengthen plant cell walls, improve nutrient uptake, and boost resistance to environmental stress. Unlike general nutrient bottles, silicon sits separately because it doesn't play well with other elements in solution—which is why this standalone additive approach actually makes sense. It's formulated specifically for hydroponic and coco systems, and works by building armour around your plants' cells, making them tougher, more productive, and better equipped to handle heat, pests, and nutrient lock-out.
How it compares
Plant Magic Silicon sits in the mid-tier of UK silicon supplements by price and performance.
- Stronger than basic silica products, specifically engineered for hydro and coco rather than a one-size-fits-all formula
- Includes balanced NPK (nitrogen, phosphorus, potassium) to aid silicon transport into plant cells—you're not just getting raw silica
- Also works as a pH buffer, helping manage acidic reservoirs without a separate pH-up product
- UK-formulated by Plant Magic's PhD-level team, not imported generic stock
Competitors like Advanced Nutrients Rhino Skin are more expensive and over-concentrated. RAW Silica is cheaper but pH-neutral, so you don't get the dual function. Plant Magic hits the sweet spot for UK growers who want proper science without paying premium markup.
Usage guidance
Silicon works best when used consistently from veg through to around two weeks before harvest. Dosing depends on your system:
Hydroponics (recirculating systems)
Dose at 0.5–1ml per litre of nutrient solution. Add to your reservoir at the start of each water change or top-up. Use with every watering.
Coco systems (hand-fed or drip)
Dose at 1–2ml per litre of water. Apply with each feed, same as your main nutrients.
Root drench (soil or pot systems)
Dilute 1ml to 2 litres of water and apply as a standard watering.
Foliar spray (optional boost)
Dilute 0.5–1.5ml per litre of water and spray plants thoroughly, hitting both tops and undersides of leaves. Best done in low light to avoid leaf burn.
Important: Monitor your pH
Plant Magic Silicon is alkaline and will raise pH in your solution. If you're running an acidic system, this is actually useful. Just check your pH regularly—don't let it drift above 6.5 in hydro.
Technical specifications
- Product type: Potassium silicate-based supplement
- Nitrogen: 0.12%
- Phosphorus: 0.03%
- Potassium: 5.06%
- Recommended dosage (hydro): 0.5–1ml per litre
- Recommended dosage (coco/soil): 1–2ml per litre
- Application window: Vegetative phase through flowering, ending ~2 weeks pre-harvest
- Available sizes: 125ml, 250ml, 1L, 5L, 10L
- pH effect: Raises solution pH (alkaline)
- Application methods: Root drench, foliar spray, reservoir additive
Who this is for
- Hydroponic growers running recirculating systems or NFT setups
- Coco growers looking to strengthen stems and prevent collapse under heavy crop loads
- Anyone dealing with environmental stress—heat spikes, pest pressure, or variable growing conditions
- Growers chasing bigger, denser yields without adding extra complexity to their feed schedule
- UK-based cultivators who value locally-formulated products backed by proper science
Particularly well suited to growers running heavy crop loads where stem strength matters, or those managing acidic hydro reservoirs where the pH-raising side benefit is genuinely useful.
Our take
This is proper silicon supplementation for people actually growing in hydro or coco. It strengthens cell walls where it counts—stems stay upright, leaves stay resilient, and you get better nutrient uptake across the board. The fact it also handles pH makes it do double duty, which is just smart formulation.
Plant Magic Silicon does exactly what a silicon product should do without the premium pricing of imported competitors. If you're running hydro or coco and not using silicon yet, this is a good time to start. Worth picking up while stock lasts.
