Trichoderma harzianum spore concentrate (makes 100 litres)

Trichoderma harzianum spore concentrate: 6.6 g vial (makes 100 litres)

A vacuum sealed vial of pure Trichoderma harzianum spores, a beneficial soil fungus that growers use as a root zone inoculant. One vial makes 100 litres of soil drench or foliar spray.

At a glance

• Type: fungal inoculant (Trichoderma harzianum spores, no carrier)
• Analysis: 3.2 × 10¹⁰ CFU per gram; 6.6 g per vial, about 210 billion viable spores
• Use for: soil drench or foliar spray on seedlings, cuttings, transplants, potting mixes and beds
• Rate: one 6.6 g vial in 100 litres of water, or 0.33 g per 5 litres
• Shelf life: a sealed vial keeps for around 2 years

What it is

Trichoderma harzianum is a fast growing fungus found in soils and on roots around the world. This vial holds 6.6 g of the spores alone, at 3.2 × 10¹⁰ CFU per gram, which is roughly 210 billion viable spores. There is no carrier to sieve out and no special equipment is needed: open the vial, mix with water, apply.

What it does

Trichoderma is a living inoculant, not a fertiliser. A dose that is a little high or low will not burn or starve a plant the way a feed can. Once the spores establish, the population follows the food on offer (root exudates, organic matter, competing fungi) and settles back into spores when the food runs out. The soil sets how dense the population gets, not the label.

Research on Trichoderma harzianum reports that it:

• grows over and feeds on other fungi, including root pathogens (mycoparasitism);
• occupies root surfaces and competes with pathogens for space and food;
• stimulates root growth, so inoculated plants often carry larger root systems;
• can switch on the plant's own defence responses (induced systemic resistance).

How to use

• Standard mix: one 6.6 g vial into 100 litres of water. Shake until dissolved.
• Smaller batch: about 0.33 g per 5 litres of water (a small pinch; the exact weight is not critical).
• Apply as a foliar spray or a soil drench.
• Use the mixed solution within 24 hours. Once in water the spores start to activate and shelf life drops sharply.
• Pairs with Bacillus subtilis concentrate: one films the root, the other hunts what gets through.

Learn more in fifteen seconds

• The root's bodyguards
• Rhizophagy: roots eat microbes

Handling and storage

• Keep the vial sealed until you use it. Sealed vials keep for around 2 years.
• Wash hands after use.
• It is a living fungus. Do not mix it in the same tank as a fungicide.
• Mix only what you can apply within 24 hours.