Trichoderma Harzianum
At A Glance
Trichoderma harzianum Rifai strain T-22 is not just a soil additive; it is a high-performance biological fungicide and root enhancer. While predatory mites guard your leaves, T-22 guards your root zone. This specific strain was hybridized to thrive across the widest possible range of soil types and temperatures, creating a living "shield" around plant roots that blocks pathogens and unlocks trapped nutrients.
Field Notes — Trichoderma T-22
| Organism | Trichoderma afroharzianum strain T-22 (formerly classified as T. harzianum, strain KRL-AG2) |
| Type | Beneficial soil fungus — root colonizer |
| Sold by | Weight |
| Formulation | Wettable powder |
| Ships as | Viable spores |
| Applied as | Soil drench, or incorporated dry into mix at potting |
| Where it lives | Root surface — colonizes and grows outward with the root system |
| Mode of action | Occupies root space ahead of pathogens, competes for nutrients and exudates, parasitizes pathogenic fungi directly, and triggers the plant's own defense response |
| Works against | Pythium, Rhizoctonia, Fusarium, Thielaviopsis, Cylindrocladium — root and crown rot organisms |
| Doesn't work against | Foliar disease (powdery mildew, leaf spot), bacterial rot, insects, fungus gnats |
| Timing | Preventive. Establishes at potting, propagation, or deflasking — before a pathogen has the root surface |
| Soil temp | Active 50–90°F; colonizes fastest 60–85°F |
| Moisture | Moist soil required for establishment; will not colonize dry media |
| Persistence | Colonizes for the life of the root system if undisturbed; reapply after repotting or heavy media change |
| Mix water | Dechlorinated. Chlorine and chloramine reduce spore viability |
| Mixed slurry | Apply the same day. Spores don't hold in solution |
| Refrigerate | Yes — refrigeration extends viable shelf life (verify against your supplier's label) |
| Compatible with | Mycorrhizae, beneficial nematodes, predatory mites, beneficial insects, springtails, most insecticides |
| Keep separate from | Systemic and broad-spectrum fungicides — chemical fungicides will kill it. Check the interval on the fungicide label before applying |
| Safe around | Pets, children, plants at any stage |
| Handling | Avoid inhaling dust when measuring dry product — mask advisable, standard for any powdered fungal product |
Target Pathogens
Environmental Needs
Selection Guide
How to Use
How They're Shipped
The Weekly Newsletter
A weekly excuse to be weird about bugs at parties.
Weekly dispatches on the quietly alarming things happening in your soil. All of it real.
No spam. Leave whenever.
You're in
The first strange true thing arrives next week.
FAQ
What is your Live Delivery Guarantee?
We guarantee that our Trichoderma T-22 arrives with a 100% viable spore count. Because you cannot see these organisms with the naked eye, our guarantee for this product is handled differently than our predatory mite or nematode guarantees.
- Viability Guarantee: We ensure that the product has been stored in climate-controlled conditions and shipped in UV-protected packaging to maintain peak potency. We guarantee the spores are "active" and ready to colonize your roots the moment they are hydrated.
- The "Proof of Life" Period: Unlike mites (which you check on day one), the proof of Trichoderma is seen in the plant's response. We offer a 21-day viability window. If you apply the product as directed and do not see an improvement in root health (whiter roots, increased root mass) or plant vigor within three weeks, contact us.
- Shipping Protection: If your package arrives punctured, wet, or has been exposed to extreme heat (left in a mailbox over 100°F) and the powder is clumped or discolored, take a photo and contact us within 24 hours. We will replace the product to ensure you are starting with a healthy colony.
Is T-22 a fertilizer?
Can I use T-22 if I already have Root Rot?
How often should I apply it?
Will it harm my Beneficial Nematodes or Soil Mites?
I see white fuzz on my soil after using T-22. Is that bad?
How does T-22 help with acclimating Tissue Culture (TC) plantlets?
Help! I'm overwhelmed
Yeah, it's a lot the first time you're using predatory mites. Please email us at info@fgmnnursery.com and we'll be happy to help!
Too Many Options?
We get it. Try our mite/insect matchmaking quiz and instantly get matched to the solutions you may need.
Mite Matters
Cucumeris: Why It Works (and Why It Fails)
Cucumeris is reliable, widely researched, and genuinely effective — within a specific set of conditions. Here's what it actually does, what it won't do, and how to tell if it's the right species for your situation.
My Plant Has Webbing. Help.
Webbing on a plant isn't always spider mites — and the mite that causes the most damage indoors doesn't produce webbing at all. Here's how to tell what you're actually looking at before you treat.
Native vs Invasive Ladybugs
Most ladybugs you'll encounter are red with black dots — and that description fits native, introduced, and invasive species equally. Here's how to actually tell them apart, what the harlequin ladybug has been doing to native populations, and where the real ecological concerns are.

















