Trichoderma is one of the many, many species of fungi that can form a symbiotic association with the roots of some plants, via mycorrhizae.
Mycorrhiza, pl. mycorrhizae: a symbiotic association between certain fungi and plant roots; characteristic of MOST vascular plants.
It has been said, for example, that the soil structure of a native tall grass prairie is as biologically diverse as the canopy of old growth rain forest. this is predominantly because of the myco-fauna. Most vascular plants, in their native habitats have some sort of mycorrhizal association.
The seeds of many vascular plant genera also depend on a fungal association to aid in germination (i.e. orchids). Basically, the fungus receives elements from the plant that would normally be unavailable in the soil, and the plant receives nutrients via the fungi that are more readily available
due to this association.
The use of mycorrhizae in GH production is fairly new (8-10 years). Many inoculation products are available commercially, such as MYCOSTOP, ROOTSHIELD, and ROOTS2 with Mycorrhiza. These products are by no means a silver bullet for perfect root health, but they have had fair results. Several CP growers have had good things to say about the use of
these products.
It is important to note that these products have been developed for the commercial greenhouse industry, they were tested and formulated for things like poinsettias and geraniums.
They will not hurt your plants, but due to the vast number of beneficial fungi found in natural mycorrhizal associations, it is safe to assume that these products will not have the same results when used for everything from palms to primula.
So, in closing. Try this stuff, take notes, read the directions, and let us know what happens.
Steve