• Black stand-up pouch of Xtreme Gardening Mykos mycorrhizal inoculant with a root and seedling graphic.
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Xtreme Gardening Mykos Granular Pure Mycorrhizal Inoculum

Xtreme Gardening Mykos Granular Pure Mycorrhizal Inoculum

$14.60
$20.85 $14.60
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Give every transplant a root network that feeds itself

Mykos is a single-species mycorrhizal inoculant containing only Rhizophagus intraradices at 300 propagules per gram. Applied directly to roots at transplant, it forms a symbiotic fungal network that extends far beyond the root zone to pull in water and nutrients the plant could never reach on its own. It works in soil, coco, peat, and rockwool, and it is compatible with both synthetic and organic fertilizer programs.

OMRI Listed CDFA Registered Single Species, No Fillers
Free shipping on orders over $49
30-day returns on all orders
Serving growers since 2006
Side by side
Untreated roots vs. Mykos-inoculated roots
No Mycorrhizae
  • Roots only absorb from their immediate surface area
  • Nutrients locked in clay or sandy pockets stay inaccessible
  • Transplant shock stalls growth for days or weeks
  • Plants wilt faster during heat or drought stress
  • Soil structure degrades without biological binding agents
  • Each plant is an island with no nutrient sharing
Mykos Granular
  • Hyphal threads extend far beyond the root zone, massively increasing absorption area
  • Fungal network mines locked-up phosphorus, zinc, copper, and moisture from surrounding soil
  • Colonizes new roots quickly, reducing transplant shock and getting plants established faster
  • Hyphal water storage acts as a buffer during heat and dry periods
  • Produces glomalin, a glycoprotein that binds soil particles and improves structure in clay or sand
  • Plants connect through the mycorrhizal network, sharing nutrients and water between root systems
What makes it different
One species, no competition, real colonization

100% Rhizophagus intraradices 300 propagules/g

No Trichoderma, no ecto-mycorrhizae, no filler species. A single endo-mycorrhizal strain means zero root competition, so colonization starts faster and stays stronger.

Works in 95% of Common Plants

Endo-mycorrhizae colonize vegetables, fruits, herbs, and flowers. Ecto-mycorrhizae (which Mykos deliberately excludes) only benefit certain trees and conifers.

Glomalin Production Improves Soil Structure

The fungal network secretes glomalin, a sticky glycoprotein that binds soil particles together. This improves water-holding capacity in sandy soils and drainage in clay.

Drought and Heat Stress Buffer

Hyphae store moisture in a sponge-like mass around the root zone, giving plants a reserve to draw from when watering is delayed or temperatures spike.

Compatible with Any Nutrient Program

Works alongside synthetic salt-based feeds, organic dry amendments, and compost teas. No need to change your existing feeding schedule.

Fresh, Live Organisms

Mykos granules contain living propagules, not freeze-dried spores. Manufactured and packaged in California by RTI, a family-owned company focused on beneficial soil microbes since 1993.

Specs
Technical details
Active Species
Rhizophagus intraradices (endo-mycorrhizal)
Propagule Count
300 propagules per gram
Formulation
Granular (for direct root contact)
Certifications
OMRI Listed, CDFA Registered Organic
Compatible Media
Soil, coco, peat, rockwool, raised beds
Manufacturer
RTI / Xtreme Gardening, California, USA
Sizes Available
1 lb ($20.85) and 2.2 lb ($32.25)
SKUs
RT4401 (1 lb), RT4402 (2.2 lb)
Safety Data Sheet (PDF)

How to apply Mykos Granular

1

Dig your transplant hole

Dig the hole to the depth of your root ball. For containers, fill with your chosen medium and leave space for the plant.

2

Add Mykos directly to the roots

Sprinkle granules into the hole and onto the root ball. Mykos must make direct contact with roots to colonize. For containers: 1 to 2 tbsp for 1 to 3 gal pots, 4 to 6 tbsp for 5 to 7 gal, 1/2 cup for 10 to 20 gal.

3

Set the plant and backfill

Place the plant in the hole, fill around it with your soil or medium, and press gently to eliminate air pockets.

4

Water in and let it colonize

Water thoroughly after planting. The fungal network will begin colonizing roots within days and continue expanding throughout the plant's life.

In the bag
What you get and which size to pick
What's in every bag
  • Granular Rhizophagus intraradices inoculant
  • 300 propagules per gram
  • No Trichoderma, no ecto-mycorrhizae, no fillers
  • OMRI Listed for organic growing
  • Application rate chart on label
Sizes we carry
  • 1 lb (RT4401): Good for 10 to 30 transplants depending on pot size
  • 2.2 lb (RT4402): Better value per ounce for growers running 20+ pots or raised beds
  • Pair with: Xtreme Gardening Azos for nitrogen-fixing bacteria alongside the mycorrhizal network
Not sure which size? The 1 lb bag handles a typical home garden or a few rounds of indoor transplants. If you run 5-gal pots or larger, the 2.2 lb bag saves about 15% per ounce. Call or email us: 716-217-0353 / help@happyhydro.com
Questions
Frequently asked questions
You can, but it is much less effective. The granules need direct contact with living roots for the fungi to colonize. Mixing it throughout the soil means most of the propagules end up too far from roots to connect. Put it in the planting hole, directly against the root ball, and you will get far better results.
The granular form works well in coco, peat, rockwool cubes, and raised beds. For hydroponic reservoirs or drip systems where you cannot place granules on roots, Xtreme Gardening makes Mykos WP (Wettable Powder), which dissolves in water. We carry that separately if you need it for an established hydro setup.
No. Mykos is compatible with both synthetic and organic nutrient programs. Very high phosphorus levels can slow colonization because the plant has less incentive to trade carbohydrates for phosphorus, but normal feeding schedules will not kill the fungi. Avoid applying fungicides directly to the root zone, as those can harm the mycorrhizal network.
For containers: 1 to 2 tablespoons for 1 to 3 gallon pots, 4 to 6 tablespoons for 5 to 7 gallon pots, 1/2 cup for 10 to 20 gallon pots, and 1 cup for 25 to 50 gallon pots. For in-ground or raised beds, use 1 to 2 tablespoons per plant placed directly in the hole. For seeds, use about 1 tablespoon per foot of row or 1/2 teaspoon per cell or plug.
One application at transplant is enough for the life of that plant. The fungal network is self-sustaining once established, feeding on carbohydrates the plant provides through photosynthesis. There is no need to reapply unless you repot into fresh medium and disturb the root system significantly.
Multi-species blends often include ecto-mycorrhizae, which only colonize trees and conifers and have no benefit for vegetables, herbs, or flowers. They can also include competing organisms that slow colonization. Rhizophagus intraradices is the most widely researched endo-mycorrhizal species and colonizes the broadest range of garden and indoor plants.
If you receive a defective or damaged unit, email us a photo at help@happyhydro.com and we'll make it right immediately: replacement or refund, your call. For change-of-mind returns, we accept returns within 30 days for items in new, resalable condition. If you're not sure whether this product is right for your setup, call us first at 716-217-0353. We'd rather answer your questions before you order.
Happy Hydro has been selling growing equipment since 2006. We've carried Xtreme Gardening for years because the systems work great and customers who buy them leave happy. Have questions before you order? Call 716-217-0353 or email help@happyhydro.com. We're easy to reach and happy to help!
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