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Mycorrhiza buying guide: class, label and pack size

Updated: October 2026

You have bare-root roses, a gap in a hedge, or peat-free pots, and amazon.co.uk is offering pouches labelled mycorrhizal fungi, Rootgrow, rooting powder and certified organic in the same scroll. A mycorrhiza buying guide should settle three things before you open the [mycorrhiza comparison](/hub/fertiliser-soil-and-bark-mulch/mycorrhiza): whether the fungus class matches the plant, whether the pouch is a named product whose weight agrees with itself, and whether 150 g or 360 g covers the session you actually have. Prices and stars below come from those listings, not a lab test. A qualifying purchase can earn a commission at no extra cost to you.

You have bare-root roses, a gap in a hedge, or peat-free pots, and amazon.co.uk is offering pouches labelled mycorrhizal fungi, Rootgrow, rooting powder and certified organic in the same scroll.

Our top picks

Empathy Empathy Rootgrow mycorrhizal fungi 360 g

Best overall

Empathy Empathy Rootgrow mycorrhizal fungi 360 g
8.8/10about £10.34
View offer
Plantworks Ltd Plantworks Rootgrow mycorrhizal fungi 150 g

Best value

Plantworks Ltd Plantworks Rootgrow mycorrhizal fungi 150 g
8.4/10about £6.79
View offer
TNC TNC MycorrHydro soluble mycorrhizal fungi 75 g

Alternative

TNC TNC MycorrHydro soluble mycorrhizal fungi 75 g
7.2/10about £14.25
View offer
On this page
  1. 1.Match the fungus to the plant
  2. 2.Named pouch versus a lookalike title
  3. 3.Pack size for one session
  4. 4.What this pouch is not

Match the fungus to the plant

Standard garden pouches here are arbuscular inoculants for most vegetables, roses, shrubs and fruit, if the product touches living roots. They do not suit brassicas. Rhododendrons, azaleas, heathers, blueberries and cranberries need an ericoid product. Empathy states that exclusion on the 360 g page, and that SKU is not among the eight kept ASINs. The Royal Horticultural Society describes the partnership as an extension of the root, most plausible in peat-free compost or worked soil. TNC MycorrHydro is the only kept listing that names NFT, flood and drain and DWC. A rose hole is the wrong job for it. That contrast sits on mycorrhiza powder vs granules.

Named pouch versus a lookalike title

Prefer a brand, a model and a pack weight that agree. Empathy and Plantworks print RG360 or RG150 with a matching gram figure. Ghjkldha B0DCVKY3HL uses the words root grow, then lists 1.0 ml, 100 g and 132 g, with country of origin China. Empathy is not on that listing. BioTabs names nine endomycorrhizal species. A certified-organic bullet is not a licence number. RootMax prints a spore count we did not measure, and the title also says rooting powder. Thousands of Rootgrow ratings are not three BioTabs ratings or five on Ghjkldha. The RHS says the UK inoculant market is largely unregulated. We did not test viability. The shortlist sits on best mycorrhiza.
Empathy Empathy Rootgrow mycorrhizal fungi 360 g

Testsieger

Empathy Empathy Rootgrow mycorrhizal fungi 360 g
8.8/10about £10.34
View offer

Pack size for one session

Plantworks 150 g is £6.79 (4.5 from 2,948 reviews). The RHS 150 g pouch is £7.59 (4.6 from 92). Manufacturer copy treats 150 g as about eight 2 L pots or one 50 L pot. That is brand coverage, not a measurement here. Close the pouch if you will use the rest later. Empathy 360 g is £10.34 (4.6 from 2,864 reviews), about 3 pence per gram, against about 29 pence per gram on BioTabs 100 g at £28.98. A hedge in one afternoon usually beats two small pouches. An opened bag left damp wastes it. The £22.78 bulb bundle is for about 50 bulbs. RootMax at £33.78 is two dry pouches at a premium price.

What this pouch is not

It is not a second fertiliser. The RHS says not to add fertiliser at the same time, because phosphorus can suppress the fungus. Hungry crops in peat-free compost still need feeding later. HSE separates biostimulant wording from pest or disease claims. Do not call a pouch a UKCA-approved biostimulant. Great Britain had no specific biostimulant framework in force on 20 October 2026. A certified-organic bullet is not a named licence. The Consumer Rights Act 2015 still covers a parcel that is not as described. Lifetime and 700% root-volume lines are manufacturer claims. Keep a named garden pouch when the plant is a host and the session fits 150 g or 360 g.

Common questions

Which plants need a standard arbuscular pouch and which need ericoid?
Standard arbuscular pouches in this set suit most vegetables, roses, shrubs and fruit, if the product touches living roots. Rhododendrons, azaleas, heathers, blueberries and cranberries need an ericoid inoculant. Empathy states those exclusions on the 360 g page. The ericoid SKU is not among the eight kept ASINs, so do not stretch a standard Rootgrow title onto a blueberry.
Will Rootgrow work on brassicas or blueberries?
No. Empathy excludes brassicas from standard Rootgrow, and blueberries need ericoid fungi. A review that reports a benefit on brassicas does not override the manufacturer exclusion. Use a different crop, or wait for a product that names that host class.
How do I tell Empathy or Plantworks from a lookalike title?
Read brand, manufacturer, model and a pack weight that agrees with the name. RG360 and RG150 with a matching gram figure are the named line in this set. Ghjkldha B0DCVKY3HL prints 1.0 ml, 100 g and 132 g and does not list Empathy. A shared phrase in the title is not the same product.
Is a 150 g pouch enough for a small planting session?
Often yes. Trade coverage treats 150 g as about eight 2 L pots or one 50 L pot, which is manufacturer copy, not our measurement. The named 150 g pouches are £6.79 and £7.59. Close the bag after the session if you will use the rest later.
When would I buy 360 g instead?
When you are planting a longer row or several large pots in one go. The 360 g Empathy pouch is £10.34, about 3 pence per gram, which usually beats two small pouches if you will empty it. It is the wrong upgrade if the opened bag will sit damp for a year.
Does a certified-organic bullet mean a Soil Association licence?
Not on the evidence in this set. BioTabs and RootMax print organic wording without a licence number. Treat the bullet as listing copy until a named scheme appears on the carton.
Is this a fertiliser, a biostimulant or a pesticide?
For this page it is a packaged fungal inoculant sold as a garden or hydro product. HSE treats nutrient-efficiency wording as a biostimulant space, not a pest-control authorisation. Do not use the pouch as a disease cure, and do not add phosphate-rich fertiliser in the same hole.

Related pages

How to use mycorrhiza

Mycorrhiza

Best mycorrhiza: garden pouch, small session or hydro

Mycorrhiza for roses when the bed already grew roses

Mycorrhiza powder vs granules: garden hole or hydro

Sources

Public UK and maker sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the eight amazon.co.uk listings in that digest. An organic bullet is not a licence number. A root-volume line and a spore count were not measured here. No pouch is treated as a cure for rose sickness or as a UKCA-approved biostimulant.

  1. RHS, Mycorrhizal fungi (retrieved 20 October 2026)
  2. RHS, Trees and shrubs planting (retrieved 20 October 2026)
  3. RHS, Biostimulants (retrieved 20 October 2026)
  4. RHS, Replant disease (retrieved 20 October 2026)
  5. HSE, Biostimulants and plant protection (retrieved 20 October 2026)
  6. GOV.UK, Manufacturing and marketing fertilisers (retrieved 20 October 2026)
  7. AHDB, How should biostimulants be used? (retrieved 20 October 2026)
  8. Empathy, rootgrow 360 g (retrieved 20 October 2026)