Silicic Acid Plant Strengthener – Grenade White MSA Max

The strongest part of a plant is the part you never see being built.

Silicon is one of horticulture's quiet over-achievers. Most base feeds barely mention it, yet plants use it to reinforce their cell walls, the same way steel bars sit hidden inside concrete. The catch is that plants can only absorb silicon in one form: monosilicic acid. Many silicon additives are potassium silicate, which has to convert before a root can use it. Grenade White skips the waiting room. It's a maximum-strength, highly stabilised monosilicic acid (also called orthosilicic acid) that's ready to go to work the moment it hits the root zone.

MSA Max – what it does

• Faster root establishment for seedlings, cuttings and fresh repots
• Increased chlorophyll production for deeper, greener growth
• Stronger stems and better plant structure – fewer flops, fewer stakes
• Greater resilience against environmental and pest stress
• Improved nutrient availability within your root zone

Seed to harvest, and everything in between

Grenade White isn't just for serious growers. It's the fix for the Monstera stem that won't hold itself up, the leggy seedlings on the windowsill, the cuttings that sulk instead of rooting, and the chilli and tomato plants that buckle under the weight of their own crop. If a plant has stems, it has a use for silicon.

Do the maths

Even at the full recommended dose of 0.4ml per litre, one 100ml bottle treats 250 litres of water – about 15p per litre. If you water a houseplant collection with a 5 litre can once a week, a single bottle lasts around a year. It's the cheapest structural engineer you'll ever hire.

How to use

• Dose: 0.4ml per litre for full effect. Use 0.2ml per litre for brand-new seedlings and fresh cuttings for their first week or two, then step up to 0.4ml. Don't go above 0.4ml.
• When: at every feed and watering, from seed or cutting all the way through to harvest. No breaks needed – silicon works by building up over time.
• Order: mix into plain water first, before any other nutrients.
• Storage: keep in a cool, dry place.

🌱 Rose's Pro-Tip

Silicic acid always goes in first, into plain water, and the order genuinely matters. Adding it after your base feed can cause it to react before your plants ever see it. Mix it fresh on the day rather than leaving a pre-made batch sitting for days – and be consistent. Silicon rewards every-feed use far more than the occasional big dose.

Better together: Grenade Black

Grenade White builds the frame; Grenade Black fills it out in bloom.

Free UK delivery on every Grenade order – no minimum spend.

Straight from the source

Black Flag Horticulture is an official Grenade Nutrients stockist, supplied direct by the brand and founder Sophie Ora. Grenade's official stockists all sell at the brand's recommended price – it's how the brand protects its quality, it's stockists and its customers – so genuine Grenade costs the same wherever you buy it properly.

Spotted it cheaper? It's worth asking where it came from. A heavily discounted bottle may not have come through official channels, which means it could be old stock, badly stored, part-used or not genuine Grenade at all – and with a product dosed at fractions of a millilitre, what's inside the bottle is the whole point. If the price looks too good to be true, it probably is.

Every bottle we send is factory-sealed and kept in climate-controlled storage until the day it ships – which matters for a stabilised silicic acid, because heat and frost are exactly what break it down – so it reaches you exactly as the maker intended. We're a real grow shop in Coventry, not a faceless warehouse, so if you've got a question about Grenade, just message us – you'll get an answer from someone who uses it.