We previously reported that growth of lisianthus [Eustoma grandiflorum (Raf.) Shinn.] seedlings is accelerated by amending the growing medium with 1% (w/w) chitosan. This finding prompted us to search for organic nitrogenous other substances like chitosan which could accelerate seedling growth. Seeds of E. grandiflorum `Peter blue line 2'were sown in a sandy loam growing medium containing 1% (w/w) chitosan, tryptone, casein, collagen or gelatin. At eleven weeks after sowing, leaf length and width, fresh and dry weights of the shoots and roots of twelve plants were determined for each treatment. Eleven weeks after sowing, the leaves at the fifth node had expanded in the chitosan, tryptone and collagen treatments while the leaves of the third node had not yet expanded in control plants. Fresh and dry weights of shoots and roots were significantly greater for plants grown in media amended with chitosan or tryptone. Percent nitrogen (N) and potassium (K) in the shoots and roots and percent phosphorus (P) in the shoots was greater only in the N side dressing treatment. The nitrate nitrogen (NO3-N) concentration was significantly greater in media amended with tryptone or collagen compared to the other treatments.