A green-house study was conducted to investigate the ability of an isolate of Trichoderma harzianum (P52) and arbuscular mycorrhizal fungi (AMF) in enhancing growth in tomato seedlings, tea and napier grass cuttings. The effect of these bio-inoculants on growth was compared with the influence of Diammonium phosphate (DAP) fertilizer and the interactions of these three factors (P52, AMF and DAP). The plants were grown in plastic pots filled with sterilized soils. A completely randomized design was used and growth measurements taken on height shoot and root dry weights. It was observed that isolate P52 and DAP fertilizer individually enhanced growth in tomatoes, tea and napier while AMF only enhanced growth in tomatoes. Combinations of P52 and DAP; P52, AMF and DAP enhanced growth significantly (P<0.05). Trichoderma harzianum and AMF showed potential for use as biofertilizers to reduce on chemical inputs in the perspective of sustainable agriculture and conservation of natural resources.