Growth Technology Liquid Silicon 5 Litre - Potassium Silicate for Stronger Stems and Roots
Best for: growers who want sturdier stems, thicker cell walls and better stress tolerance across veg and flower, in soil, coco or hydro.
Our thoughts
Silicon additives get overlooked because they're not flashy - no headline yield claims, just plants that hold themselves up better and shrug off stress more easily. This is a genuinely useful bit of kit for the price, especially if you're growing anything top-heavy or running a system that's a bit hit-and-miss on humidity. The 5 litre size makes sense once you're using it as a standard part of your routine rather than a one-off try.
Growth Technology Liquid Silicon is a 6% potassium silicate solution used as a strengthening additive alongside your normal feed. Silicon isn't one of the standard NPK nutrients, but it's absorbed by plants and deposited in cell walls, where it adds physical strength to stems and improves resistance to pests, disease and general stress.
Standard dose is 0.5ml per litre of water, rising to 1ml per litre if you're using reverse osmosis or very soft source water. The aim is to keep silicon in the 20-50ppm range in your nutrient solution. It can be used right through from vegetative growth into flowering, and works in hydroponics, coco or soil substrates. Because it's alkaline, it can also nudge pH upward slightly, so it's worth checking your pH after adding it, especially if your solution already runs low.
How it compares
Silicon additives are a fairly established category, and Growth Technology's version sits solidly in the mainstream on concentration and price.
- General Hydroponics Armor Si is a well-known US-formulated alternative, typically priced higher per litre than Growth Technology's version.
- House & Garden's Silicon additive is popular in the UK and works on a similar potassium silicate basis, but at a noticeably higher cost per dose.
- Canna Boost isn't a direct silicon product but often gets bought for similar "plant toughening" reasons - Liquid Silicon does the strengthening job more directly and more cheaply.
You're getting a straightforward 6% potassium silicate solution at a lower cost per litre than most of the branded alternatives, with no compromise on what it actually does.
Usage guidance
Standard water
Add 0.5ml per litre of nutrient solution or water at every feed.
RO or soft water
Increase to up to 1ml per litre, since soft or osmosis water carries little to no natural silicon.
Adding to the tank
Add Liquid Silicon to your reservoir before other nutrients where possible, and always dilute additives separately rather than pouring concentrates directly onto each other.
pH check
Because Liquid Silicon is alkaline, recheck your solution's pH after dosing and adjust down if needed.
Technical specifications
- Active ingredient: potassium silicate (6%)
- Volume: 5 Litre (also available in 250ml and 1 Litre)
- Standard dose: 0.5ml per litre
- RO/soft water dose: up to 1ml per litre
- Target silicon level: 20-50ppm in solution
- Compatible media: hydroponics, coco, soil
- Growth stage: vegetative through flowering
- Manufacturer: Growth Technology
Who this is for
- Growers with tall or top-heavy plants needing sturdier stems
- Anyone growing in humid conditions where mould and pest pressure is higher
- RO water users who need a silicon source their water doesn't provide
- Larger grows wanting the better cost-per-litre of the 5L size
Particularly worth it if you've had stem snap, mildew or spider mite problems in the past and want an easy preventative step.
Our take
Liquid Silicon isn't going to be the additive that gets talked about at the grow shop counter, but it does a genuinely useful job - stronger stems, tougher cell walls and better resistance to the stresses that knock a grow off track. The 5 litre size brings the cost per dose right down for anyone using it regularly.
Does exactly what it should, day in, day out. Worth picking up if you want your plants to hold themselves together better without adding complexity to your feeding schedule.
