A laboratory experiment was carried out to study the effect of inoculation with some non-symbiotic nitrogen fixing diazotrophs (Azospirillum liopferum, Azospirillum brasilense, Azotobacter chroococcum) in addition to Bacillus polymyxa either each in free or encapsulated in alginate beads on seed germination and growth of some vegetable plants such as lettuce, onion and carrot. Results revealed that all the tested bacterial strains, when entrapped in alginate had significantly higher nitrogenase activity and in turn higher nitrogen fixation efficiency than that achieved by the free bacterial cells. When the encapsulated alginate bacteria were inoculated to any of the tested vegetable seeds they surpassed those of inoculated free cells in affecting their seeds germination and growth. However, encapsulated Azospirillum brasilense was superior for lettuce, encapsulated Azospirillum liopferum was superior for onion and encapsulated Azotobacter chroococcum was superior for carrot, all in increasing seed germination per cent, the radical and epicotyl lengths, seedlings fresh and dry weights and leaves chlorophyll contents compared to their corresponding free bacterial cells.