De-oiled cakes of four trees born oilseeds (TBOs) viz., Neem, Jatropha, Mahua and Karanja were tested for their suitability for mass multiplication of T. harzianum and also that for how long they are able to support the survival of T. harzianum with the considerable level of population dynamics of T. harzianum. In addition to these four de-oiled cakes, two composts i.e., FYM and Vermicompost were also tested for their suitability and to have a comparison with these de-oiled cakes in supporting population dynamics and longevity of T. harzianum. Among four de-oiled cakes viz neem, jatropha, mahua and karanja, neem cake was found to be best substrate for supporting the population dynamics and longevity of T. harzianum in vitro. Neem cake maintained with 25% moisture was able to support the longevity of T. harzianum for more than 105 days with a considerable level of population, whereas Jatropha, Mahua and Karanja cakes could support the longevity of T. harzianum up to 90 days only. Mixing of pre grown Trichoderma harzianum on potato dextrose broth (PDB) to the four de-oiled cakes resulted in comparatively better population dynamics than that when it was grown on Potato Dextrose Agar.