The root stimulator UK growers trust — now better

Canna Rhizotonic is a concentrated natural extract of North Atlantic seaweed (Ascophyllum nodosum) — the root enhancer and stress reliever most UK growers started with, and the new improved formula is the biggest update in its history. It helps cuttings, seedlings and transplants throw down a productive, healthy root system fast, which means better water and nutrient uptake and a plant that can shrug off stress instead of stalling.

A strong root zone is the foundation of every harvest. More root mass means faster uptake, quicker establishment after re-potting, and real resilience against heat and drought shock. Rhizotonic is where that foundation gets built.

What's new in the improved formula

More concentrated seaweed extract. A revised production process boosts the organic compounds that trigger the plant's own root-growth hormones.
Plant-friendly pH (~4.7, down from ~12.5). Solutions need far less correction, and the old formula's fishy smell is largely gone — the new version smells sweeter and pours slightly darker.
Two-year shelf life in the bottle (double the old formula) and high stability once diluted.
Minimal EC contribution — gentle enough for germination, where it helps soften hard seed casings so the tap root emerges more easily.

(Sold in North America as "Rhizotonic XP" — same update, different regional name. UK stock carries standard Rhizotonic labelling.)

Why growers use Rhizotonic

Rapid new root growth on cuttings, seedlings and freshly re-potted plants
Stress relief and recovery — re-potting shock, heat, drought
Works on any substrate: soil/peat mixes, coco, and inert hydro media like pebbles and rockwool
Suitable as a foliar spray for a direct route into stressed plants
Can support healthy substrate micro-life; seaweed extracts of this type have also been linked to improved flavour and quality in the finished harvest
Vegetable-based formula rich in organic compounds, vitamins and minerals

Genuine UK stock — why it matters

All our Canna stock is sourced through the official UK supply chain: English-language labels with UK dosing instructions, the current new-formula bottles (best-before March 2028 or later), and full manufacturer backing. Cheaper listings you may see elsewhere are often grey imports labelled for the Spanish or French markets — older stock, foreign-language instructions, and no UK support chain behind them. With a formula this recently updated, knowing exactly which version is in the bottle matters.

How to use Canna Rhizotonic (dosage)

Shake the bottle well before use, and always correct pH after adding your base nutrients and additives.

Stage	Dose
First dose & re-potting	40ml per 10L (4ml/L)
Vegetative growth	20ml per 10L (2ml/L)
Generative (flowering)	5ml per 10L (0.5ml/L)

Use the full first-dose rate whenever you re-pot.
In recirculating or drip systems, renew the nutrient solution every 5–7 days — Rhizotonic is organic material and shouldn't sit in tanks or lines indefinitely.
Don't be tempted to overdose: over-fertilisation harms the substrate and the plant. The tiered rates above are the schedule.
For cuttings and stressed plants, a foliar mist gets Rhizotonic in fastest.

At a glance


Type	Root stimulator / stress reliever
Base	Ascophyllum nodosum North Atlantic seaweed extract
Formula	New improved formula ("XP" outside the UK)
Dosage	40 / 20 / 5 ml per 10L (first dose / veg / flower)
Media	All substrates — soil, coco, hydro
EC	Minimal addition when diluted
pH	~4.7 (was ~12.5) — correct pH after all additions
Shelf life	2 years — store closed, dark, frost-free
Sizes	250ml · 1L (stocked) — 5L/10L exist in the range, not currently stocked

Old formula vs new formula

	Old Rhizotonic	New Rhizotonic
Algae concentration	Standard	Increased
pH	~12.5	~4.7
Smell	Fishy/sulphurous	Sweeter
Shelf life	12 months	24 months
Dilution rates	40/20/5 per 10L	Unchanged

Frequently asked questions

Is this the new formula / "Rhizotonic XP"?

Yes. All stock we ship is the new improved formula. "XP" is the name used for the same update in North America — UK bottles carry standard Rhizotonic branding. New-formula bottles have a best-before date of March 2028 or later, a sweeter smell, and a slightly darker pour.

How much Rhizotonic per litre?

4ml/L for the first dose and whenever you re-pot, then 2ml/L through veg and 0.5ml/L in flower. Shake well first, and correct pH after adding everything to the solution.

Can I use Rhizotonic in soil / coco / hydro?

Yes — it's suitable for every substrate and irrigation system, from peat mixes and coco to pebbles and rockwool. It pairs naturally with Canna Terra Professional Plus in soil and Coco Professional Plus in coco — see our Canna feed chart guide for full schedules by medium.

Do I stop using it in flower?

No — you taper, not stop. The generative rate is 0.5ml/L. In flower it works alongside Cannazym for root-zone maintenance, Canna Boost and PK 13/14.

Does the new formula change my pH routine?

Possibly. The old formula's pH ~12.5 pushed solutions up; the new ~4.7 doesn't. Keep checking as normal — depending on your water you may now need less correction, or a nudge upward rather than down.

Can I use it from seed?

Yes — its low EC makes it germination-friendly, and it can help soften hard seed casings so the tap root breaks through more easily.

How long does a bottle last?

Two years unopened/closed, stored dark and frost-free. Once diluted it stays stable, but renew reservoir solution every 5–7 days in recirculating or drip systems.