• Mycorrhizal Fungi Powder — 40g kraft pouch with dr forest Organic Mycorrhizal Fungi Endo and Ecto label
  • Mycorrhizal Fungi Powder — hands sprinkling tan powder over tomato seedling root ball above prepared soil
  • Mycorrhizal Fungi Powder — With vs Without Mycorrhizae comparison: lush red tomato plant vs sparse green seedling
  • Mycorrhizal Fungi Powder — young apple tree with extensive cutaway root system visible below the soil line
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Dr Forest

Mycorrhizal Fungi Powder UK | 18 Species (9 Endo + 9 Ecto) | Plant-Based Root Inoculant

Mycorrhizal Fungi Powder UK | 18 Species (9 Endo + 9 Ecto) | Plant-Based Root Inoculant

£6.99 GBP
£6.99 GBP
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Mycorrhizal fungi powder — an 18-species endo and ecto root inoculant

18 Species 9 Endo + 9 Ecto Sourced Fresh Plant-Based No Fillers Fine Powder

Mycorrhizal fungi powder is a root inoculant — living fungal spores you apply at planting so the fungi colonise the roots and extend them out through the soil. Once colonised, the plant trades a little sugar for a vast secondary network of fungal threads that pull in phosphorus, water and trace minerals from soil the roots cannot reach on their own. Dr Forest's is an 18-species blend of 9 endomycorrhizal and 9 ectomycorrhizal fungi, milled to a fine powder so the spores sit in direct contact with the feeder roots, which is where colonisation actually begins.

Modern growing strips this partnership out. Bagged compost is sterilised, peat-free mixes start with no native fungi, and pot-raised nursery stock is grown on high-phosphate feeds and fungicides that suppress colonisation. Take that plant out of its pot and into the garden and it has no fungal partner. That is why new trees stall in their first seasons, transplants sulk, and roses planted where roses grew before fall into replant disorder. Inoculating at the moment of planting puts the partner back.

A plant-based alternative to bone meal at planting

A root inoculant for gardeners who would rather not reach for bone meal, fish blood and bone, or other slaughterhouse by-products when they plant. Mycorrhizal fungi do the establishment job those products are bought for, improving root reach and phosphorus uptake, with no animal inputs. Pair it with a light, low-phosphate organic feed rather than a high-phosphate one.

18Fungal Species
9 + 9Endo & Ecto
80–90%Of Plants Benefit
1–1.5gPer Litre Root Ball

What it's used for

  • Planting and transplanting — dust or dip the root ball as you plant trees, shrubs, perennials and veg starts; colonisation begins at the point of contact
  • Transplant shock and establishment — gives new and pot-raised plants the fungal partner they were grown without, so they push fresh roots instead of stalling
  • Fruit trees — apple, pear, plum and cherry establish faster and reach water and phosphorus in poor ground
  • Roses, including replant disorder — re-introduces mycorrhizae to beds where roses grew before, one of the recognised ways to ease the stall
  • Drought and stress resilience — the hyphal network reaches moisture well beyond the root zone
  • Poor and depleted soils — improves phosphorus uptake where soil reserves are locked up and roots struggle to find them

Why 18 species, not five

Most UK inoculants are single-species or built on a handful of strains. Different fungi partner with different plants and thrive in different soils, so a wider blend colonises more of what you actually grow. This powder carries 9 endomycorrhizal species (for the 80–90% of garden, vegetable, fruit and flower plants that form arbuscular associations) and 9 ectomycorrhizal species for the many trees and shrubs that need the other type. One pouch covers a mixed garden rather than a single crop.

The species in the blend

Endomycorrhizae — 9 species (arbuscular)

  • Rhizophagus irregularis (Glomus intraradices)
  • Funneliformis mosseae (Glomus mosseae)
  • Glomus aggregatum
  • Claroideoglomus etunicatum (Glomus etunicatum)
  • Glomus deserticola
  • Rhizophagus clarus (Glomus clarum)
  • Glomus monosporum
  • Paraglomus brasilianum
  • Gigaspora margarita

Ectomycorrhizae — 9 species

  • Pisolithus tinctorius
  • Rhizopogon villosulus
  • Rhizopogon luteolus
  • Rhizopogon amylopogon
  • Rhizopogon fulvigleba
  • Scleroderma cepa
  • Scleroderma citrinum
  • Laccaria bicolor
  • Laccaria laccata

Several of the endo species were reclassified out of the old genus Glomus, so spec sheets and rival products may list either name — the familiar Glomus name is shown in brackets where it differs.

Fine powder format

  • Dusts straight onto the feeder roots at planting — direct spore-to-root contact
  • Mixes into a thin slurry for dipping bare roots and root balls
  • Higher colonisation because the spores start where the roots are
  • Goes further per gram than a coarse carrier

Granular format

  • Sits in the backfill and relies on roots growing out to find the spores
  • Coarser contact at the critical moment of planting
  • Slower, more hit-and-miss colonisation
  • More carrier bulk per dose of live spores

Handcrafted in small batches in Stockport. Plant-based, with no animal by-products — Dr Forest.

The science: how mycorrhizal fungi colonise roots and move phosphorus

Mycorrhizae are not a fertiliser. They are a symbiosis around 450 million years old, in which fungi colonise plant roots and grow a network of ultra-fine threads (hyphae) out into the surrounding soil. The plant supplies sugars from photosynthesis; the fungi return phosphorus, water, nitrogen and trace elements gathered from a soil volume many times larger than the roots could explore alone. Phosphorus is the headline benefit, because it barely moves in soil: roots quickly strip the zone immediately around them, and hyphae bridge the gap to the phosphorus beyond.

Why spore viability is the only number that matters

Independent testing has repeatedly found that many shop-bought mycorrhizal products contain too few living spores to do anything. A 2025 meta-analysis of 302 trials reported that fewer than 12% of commercial inoculants produced both viable colonisation and a measurable growth benefit, and that around 84% failed to produce meaningful root colonisation at all (Koziol et al., 2025). Species counts and propagule claims mean nothing if the spores are dead on arrival. Dr Forest buys this inoculant in small batches with fresh stock arriving every month, so the spores leave here fresh rather than after a year on a warehouse shelf, and every pouch carries an honest 9–12 month use-by because viability falls over time. Store it cool and dry, and use it inside that window for the best colonisation.

Six mechanisms of action

01

Hyphal extension of the root system

Fungal hyphae are far finer than root hairs and grow out through pores roots cannot enter, extending the plant's effective reach several-fold. This is what lets a colonised plant draw water and immobile nutrients from soil its own roots never touch: the foundation of every other benefit below.

02

Phosphorus delivery

Endomycorrhizae form arbuscules inside root cells — branched structures that hand phosphorus directly to the plant. Because phosphate ions diffuse so slowly through soil, a plant's own uptake is limited to a thin depletion zone around each root; the fungal network reaches well past it. Smith & Read (2008) document this as the central nutritional role of the symbiosis.

03

Glomalin and soil structure

Arbuscular fungi exude glomalin, a sticky glycoprotein that binds soil particles into stable aggregates. The result is better porosity, aeration and water-holding — improvements that outlast the growing season and feed back into healthier rooting (Rillig, 2004).

04

Drought and stress tolerance

Colonised plants hold leaf water potential and keep photosynthesising for longer under drought, and tolerate salinity and heavy-metal stress better. Reviews of abiotic-stress trials attribute this to improved water capture through the hyphal network and to changes in the plant's own stress physiology (Begum et al., 2019).

05

Endo versus ecto: two partnerships, one bag

Endomycorrhizae (arbuscular, AMF) grow inside root cells and partner with most garden, vegetable, fruit and flower plants. Ectomycorrhizae sheath the root surface in a fungal mantle and partner with many trees and shrubs — birch, beech, oak, pine. Carrying both types, across a wide species range, is why one product works across a mixed planting (van der Heijden et al., 1998, on why fungal diversity raises plant productivity).

06

Where it does nothing: the honest scope

Around 10–20% of plants form no functional association and gain nothing from inoculation: the brassica family, beets and spinach, and ericaceous plants such as blueberries, rhododendrons and heathers (which use a different, ericoid partnership). On these, save the powder for something that will use it.

Evidence on fruit and vegetable crops

On crops that do partner, the gains are well documented. A 2023 field study on citrus reported heavier, sweeter fruit with higher vitamin C after arbuscular inoculation, alongside improved soil phosphorus availability (Zhou et al., 2023). Field trials on tomato have shown higher fruit fresh weight and markedly higher lycopene, the antioxidant pigment behind the red colour, in mycorrhizal plants than in uninoculated controls (Aguilera et al., 2022). The pattern across the literature is consistent: better phosphorus nutrition, better stress tolerance, better fruit quality, provided the spores were alive to begin with.

Feed the partnership, not just the plant — a colonised root system does the work a bag of fertiliser cannot.

Scientific references

  1. Smith, S.E. & Read, D.J. (2008). Mycorrhizal Symbiosis, 3rd ed. Academic Press.
  2. van der Heijden, M.G.A. et al. (1998). Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability and productivity. Nature, 396, 69–72.
  3. Koziol, L., McKenna, T.P. & Bever, J.D. (2025). Meta-analysis reveals globally sourced commercial mycorrhizal inoculants fall short. New Phytologist. doi:10.1111/nph.20278.
  4. Koziol, L., Lubin, T. & Bever, J.D. (2024). An assessment of twenty-three mycorrhizal inoculants reveals limited viability of AM fungi, pathogen contamination, and negative microbial effect on crop growth. Agriculture, Ecosystems & Environment.
  5. Rillig, M.C. (2004). Arbuscular mycorrhizae, glomalin, and soil aggregation. Canadian Journal of Soil Science, 84, 355–363.
  6. Begum, N. et al. (2019). Role of arbuscular mycorrhizal fungi in plant growth regulation: implications in abiotic stress tolerance. Frontiers in Plant Science, 10, 1068.
  7. Zhou, Y. et al. (2023). Positive changes in fruit quality, leaf antioxidant defense and soil fertility of Beni-Madonna tangor citrus after field AMF inoculation. Horticulturae, 9(12), 1324.
  8. Aguilera, P. et al. (2022). Arbuscular mycorrhizal fungi from acidic soils favours production of tomatoes and lycopene concentration. Journal of the Science of Food and Agriculture, 102(7), 2756–2763.

How to use mycorrhizal inoculant: rates, slurry dip and planting method

Contact beats dose

The single thing that matters is getting live spores onto the feeder roots at planting. A light, even coating in direct contact with the roots colonises far better than a heavier dose scattered nearby or raked into the surface. You can apply more without harm, since the fungi self-regulate colonisation to the plant's needs, but more powder is no substitute for good contact.

Application rates

Potted plants & transplanting

Rate: 1–1.5 g per litre of root-ball volume  |  When: Once, at planting

Apply directly to the roots — dusting or drenching the root ball itself ensures maximum contact with the feeder roots and far better colonisation than adding it only to the hole or backfill.

Cuttings

Rate: A light dip  |  When: At striking

Lightly moisten the base of the cutting and dip it straight into the powder before planting.

Seed

Rate: 300 g per 750 m²  |  When: At sowing

Mix with the seed before sowing, or dust lightly into the seed drill so spores sit alongside the germinating roots.

Three ways to apply at planting

  1. Dust over the root ball. Use an icing-sugar shaker or a fine tea sieve to coat the root ball evenly and lightly, without clumping. Quick, and ideal for potted stock.
  2. Slurry dip. Mix the powder with a little water at roughly a 1:3 to 1:5 powder-to-water ratio to make a thin, paint-like slurry. Stir to suspend it, then pour over, brush on, or dip the root ball before planting. Let excess drain, then plant. Best for bare-root trees and roses.
  3. Into the planting pit. Place the powder in the base of the hole or mix it through the backfill that will sit against the feeder roots. Use when dusting or dipping isn't practical.
Keep phosphate low while it establishes

Mycorrhizae establish even in poor soil, but perform best when planted into ground rich in organic matter. If you feed, use a light dose of a slow-release, low-phosphate organic feed — high phosphate signals the plant it doesn't need a fungal partner and suppresses colonisation. Once established, mycorrhizal plants need far less feeding. Most herbicides and insecticides that are safe for the plant don't interfere; if a fungicide is unavoidable, check compatibility first.

Works well with…

Follow up a few days after planting with Dr Forest seaweed powder as a transplant biostimulant to support early root recovery, and feed established plants with the matching crop feed (Tomato, Rose & Flower, or the Veg & Bloom range) once the partnership has taken hold. Browse the full range over on the Dr Forest shop, and read more in our guide to mycorrhizal fungi on the blog.

Frequently asked questions about mycorrhizal fungi powder

Yes — the symbiosis itself is one of the best-documented in plant science. The real catch is product quality: independent testing has found that many shop-bought inoculants contain dead or too few spores, with fewer than 12% of commercial products in a 2025 meta-analysis producing both colonisation and a growth benefit. That's why spore viability matters more than any marketing claim. Dr Forest buys this inoculant in small batches with fresh stock in every month, so you're applying living spores, not old warehouse stock, and every pouch carries an honest 9–12 month use-by. It works best when applied at planting, on plants that form the partnership, in low-phosphate conditions.
No. Around 80–90% of plants form the partnership and benefit; about 10–20% don't. Skip it on the brassica family (cabbage, kale, broccoli, cauliflower, sprouts, turnip, radish), on beets and spinach, and on ericaceous plants (blueberries, cranberries, rhododendrons, azaleas, heathers). On those it gives no benefit, so save it for plants that will use it.
Apply it at planting, in direct contact with the roots. You can dust it evenly over the root ball, mix it into a thin slurry and dip the roots, or place it in the planting hole where new roots will grow. Contact at the moment of planting is everything — scattering it on the soil surface afterwards does very little.
For potted plants and transplants, 1–1.5 g per litre of root-ball volume. You can use more without harm — the fungi self-regulate colonisation to the plant's needs. For seed, mix at 300 g per 750 m², or dust it into the seed drill.
Yes. It's plant-based with no animal by-products, and it does the establishment job gardeners often reach for bone meal or fish blood and bone to do at planting, improving root reach and phosphorus uptake. Pair it with a light, low-phosphate organic feed rather than a high-phosphate bone product, which would suppress the fungi.
Yes — apple, pear, plum, cherry and most top fruit form the partnership. Dust or dip the roots at planting; the hyphal network helps a young tree reach water and phosphorus while it establishes, which is exactly when it's most vulnerable to stalling.
No, not in undisturbed soil. Once established, the fungal network persists and sustains itself. Re-apply where the soil has been dug over, sterilised, fumigated or left fallow, and whenever you plant something new. Those are the situations where native fungi are missing.
Yes. Roses are mycorrhizal, and inoculating at planting is one recognised way to reduce rose replant disorder — the stall you see when a new rose goes into a bed where roses grew before. Dip or dust the roots as you plant.
Endomycorrhizae (arbuscular, or AMF) grow into the root cells and partner with most garden, vegetable, fruit and flower plants. Ectomycorrhizae sheath the root surface and partner with many trees and shrubs, such as birch, beech, oak and pine. Most products carry only one type; this blend carries both, across 18 species, so one pouch covers a mixed garden.
Keep it cool, dry and out of direct sunlight. The spores are living, so viability declines over time — use within 9–12 months of purchase for the best colonisation. Stock here is bought in small batches and refreshed monthly, so what arrives with you is fresh rather than long-warehoused.
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