In organic / GACP cultivation, you’ve probably heard these terms tossed around: mycorrhizae, Trichoderma, Bacillus, Pseudomonas, antagonistic fungi…
They sound “scientific,” but they’re actually very practical – all are beneficial microorganisms that help keep your garden healthy, reduce disease, and cut down on chemical inputs.
Here’s a concise overview for everyone to study and discuss.
Mycorrhizae – Symbiotic Root Fungi
Mycorrhizae = fungi living in symbiosis with plant roots.
- Fungal hyphae attach to the roots, then spread through the soil like a “supplementary root network”
- The plant provides the fungi with sugars (carbon); in return, the fungi help the plant:
- Absorb more water and nutrients (especially P and trace elements)
- Better withstand drought, heat, and transplant shock
- Reduce the risk of root rot / nutrient deficiency
Put simply:
Mycorrhizae = an “extended root system + backup immune system” for your plants.
Product examples: MYKOS, Great White, and various “mycorrhizae inoculant” products.
Trichoderma – The Good Fungus That Takes Down the Bad Ones
Trichoderma is a genus of beneficial fungi living in the soil, around the root zone.
- It competes for space and food with pathogenic fungi
- It secretes enzymes that latch onto the hyphae of disease-causing fungi like Fusarium, Pythium… and literally “eats” the competition
- At the same time, it stimulates the plant to:
- Produce new roots
- Break down organic matter → easier nutrient uptake
→ In organic growing, Trichoderma is one of the “must-have weapons” if you want to minimize chemical use.
Bacillus – Extremely Useful Soil Bacteria
Bacillus is a family of rod-shaped bacteria with many species highly beneficial for plants:
- Bacillus subtilis, B. amyloliquefaciens… → produce natural antibiotics that suppress pathogenic fungi on leaves and roots
- Bacillus thuringiensis (Bt) → produces targeted toxins that kill caterpillars (leaf-eating larvae, webworms…)
Benefits:
- Protects plants from certain fungi and pest insects
- Aids organic matter decomposition, nutrient fixation
- Safe for IPM / organic / GACP use, leaves no toxic residue
Pseudomonas – Growth-Promoting Bacteria (PGPR)
Pseudomonas is a group of bacteria living around roots, with many strains classified as:
PGPR – Plant Growth-Promoting Rhizobacteria
(root-zone bacteria that stimulate plant growth)
Some strains:
- Secrete plant hormones (auxin, gibberellin…) → enhanced root development
- Secrete natural antibiotics → suppress pathogenic fungi and bacteria
- Help plants absorb phosphorus and trace elements more efficiently
Result:
Plants “eat well, grow fast,” get sick less – especially in the root zone.
What Are “Antagonistic Fungi”?
Antagonistic fungi is a general term for beneficial fungi that specialize in fighting pathogenic fungi.
- Example: Trichoderma is the most prominent antagonistic fungus
- Mechanisms:
- Race to occupy space and food sources against harmful fungi
- Attach to pathogenic fungi and secrete enzymes that perforate and dissolve their hyphae
- Some species also trigger the plant’s immune system
Role in the garden:
- Protect roots from soil-borne fungal diseases
- Reduce the risk of “garden collapse” when humidity / rootzone conditions aren’t perfect
- A critical foundation for living soil, organic, and GACP cultivation
Quick Summary
- Mycorrhizae → symbiotic root fungi that help absorb nutrients + water, boosting plant health
- Trichoderma → good fungi that “punch out” disease-causing fungi in the soil
- Bacillus & Pseudomonas → beneficial bacteria around roots that both protect and stimulate plants
- Antagonistic fungi → general term for beneficial fungi that fight pathogens (Trichoderma is example #1)
If you’re interested, future articles could cover:
- How to use mycorrhizae / Trichoderma / Bacillus in soil, coco, and hydro
- Brands / products commonly used in GACP cultivation across EU/US/Asia
- How to combine microbes with mineral fertilizers without “killing” them
If you’re using myco / Trichoderma / Bacillus, share your experiences, root photos & before–after comparisons so we can all learn together.
Disclaimer: This article is for educational purposes only, in compliance with the Controlled Herbs (Cannabis) Notification 2025 and Ministerial Regulation B.E. 2569 of Thailand. Cannabis cultivation requires proper licensing. No recreational use promotion.
They can be used together and should be used together – the synergistic effect is excellent.
Avoid: strong fungicides/bactericides, fertilizer solutions “soaked for too long,” and overly harsh EC/pH levels.
Mix and water immediately, and re-inoculate microbes after each “heavy sterilization.”
