<p>The use of biochar and beneficial bacteria as biofertilizers is gaining increasing attention as a means to reduce the reliance on agrochemical inputs in future agriculture. However, the dynamics of introduced bacteria in biochar-amended soils, as well as the additive effects of bacteria and biochar during the early stages of plant growth, are still poorly characterized. First, a synthetic bacterial community was formulated and its ability to survive was assessed in both non-amended and biochar-amended soils. Secondly, both the individual and combined effects of biochar (applied at 10% (w: w)) and a consortium of five bacteria (<i>Bacillus sp.</i> strain B1, <i>Bacillus velezensis</i> strain Bv1, <i>Bacillus pumilus</i> strain Bp1, <i>Bacillus licheniformis</i> sp. strain Bl1 and <i>Priestia megaterium</i> strain Pm1) isolated from a bio-fertilizer were examined on various biometric and physiological traits of young tomato (<i>Solanum lycopersicum</i> L. var. Principe borghese) plants. At the seedling stage, the sole application of bacteria increased hypocotyl length by 25%, but decreased radicle length compared to non-treated soils. At the plantlet stage, bacteria alone further increased both shoot length by and leaf surface area by 13% and 22%, respectively, but decreased leaf chlorophyll content. On the other hand, co-application of biochar and bacteria partially restored leaf chlorophyll content to control levels, and showed additive effects improving the fresh and dry weight of aboveground tissues by ~ 30% compared to untreated soils. Biochar amendment decreased leaf N content both in the presence and absence of bacteria, suggesting a possible N immobilization in biochar particles which could reduce its availability for the plant. These results point biochar as a suitable material for the survival and viability of synthetic bacterial communities, and show that biochar and the tested inoculum can additively improve key attributes in young tomato plants.</p>