How to Use Mycorrhizae and Trichoderma in Your Next Grow: Application Schedule and Visible Results

If you've ever noticed your plants stalling in growth, developing weak roots, or suffering stress after transplanting, their root system likely needs a biological boost. Mycorrhizae and trichoderma are not just any fertilizer—they are beneficial fungi that establish a real symbiosis with roots, improving nutrient uptake and protecting against pathogens. In this article, I explain how to apply them in your grow, with a step-by-step schedule and what results you can expect.

What Are Mycorrhizae and Trichoderma and Why Do They Work Together?

Mycorrhizae (from Greek mycos = fungus, rhiza = root) are fungi that colonize plant roots, extending their mycelium into the substrate. This mycelium acts as an extension of the root system, increasing the surface area for water and nutrient absorption—such as phosphorus, nitrogen, and micronutrients—by up to 100 times. On the other hand, trichoderma are antagonistic fungi that combat soil pathogens like Fusarium, Pythium, and Rhizoctonia, while also stimulating the plant's immune system.

When applied together, they create a balanced root ecosystem: mycorrhizae maximize nutrition, while trichoderma protect the rhizosphere. Products like [product:myco-rizas-anarkia81-50-g] or [product:myco-rizas-anarkia81-100-g] contain mycorrhizal spores ready to inoculate your substrate from day one.

Application Schedule: From Seed to Flowering

Week 1-2: Germination and Pre-Transplant

Action: Inoculate the substrate before sowing or at the time of transplanting into the final pot.

• Mix 2-3 grams of mycorrhizae per liter of substrate (for 5-10 L pots, use 10-15 g).
• Lightly moisten the substrate to activate the spores.
• If using trichoderma, apply 1 g/L in the initial watering water.

Visible result: The first roots will appear thicker and with abundant root hairs within 7-10 days.

Week 3-4: Vegetative Growth

Action: Reapply trichoderma every 10-14 days.

• Dilute 1 g/L of trichoderma in watering water (pH 5.8-6.2 for coco, 6.0-6.5 for soil).
• Do not combine with chemical fungicides; wait at least 48 hours after any treatment.

Visible result: Leaves show a more intense green color and internodes shorten. The plant shows greater tolerance to irregular watering.

Week 5-6: Pre-Flowering

Action: Second inoculation of mycorrhizae if the substrate is inert (coco, rockwool).

• Sprinkle 5-8 g around the root collar and water immediately.
• Keep watering EC between 1.2 and 1.6 mS/cm (according to the Nutrition and Climate Manual), avoiding salt spikes that damage the mycelium.

Visible result: Roots begin to emerge from the pot's drainage holes, white and branched. Aerial growth accelerates.

Week 7-8: Start of Flowering

Action: Weekly application of trichoderma to prevent root rot.

• Use 0.5 g/L in each watering during the first 2 weeks of flowering.
• Reduce frequency if you observe excess moisture in the substrate.

Visible result: Flowers develop more uniformly and the smell of wet soil (geosmin) intensifies, a sign of healthy microbial activity.

Week 9-12: Advanced Flowering and Flush

Action: Stop applications 2 weeks before harvest.

• During the final flush (last 7-10 days), water only with pH 6.0 water to remove residual salts.
• Mycorrhizae and trichoderma have already established a stable colony; no further inputs are needed.

Visible result: Buds are denser and more resinous. At harvest, roots appear white and fibrous, with no signs of necrosis.

Visible Results You Can Expect

• Greater nutrient uptake: Plants fed with mycorrhizae typically require 20-30% less fertilizer to achieve the same development. Drainage EC remains more stable.
• Drought stress resistance: The mycelium retains water in the substrate, allowing you to space out waterings without wilting.
• Prevention of root diseases: Trichoderma compete for space and secrete enzymes that degrade the cell walls of pathogenic fungi. According to the Technical Manual for Integrated Pest Management, this reduces the incidence of damping-off in seedlings by up to 70%.
• More extensive roots: At harvest, you'll notice the root ball is larger and covered in white mycelium.