The effect of organic sources of nutrients on the growth of spring barley (Hordeum vulgare L.) was studied in a pot experiment in a heated glasshouse at the University of Wales, Aberyswyth from November 2006 to March 2007. Spring barley seeds were sown in 120 pots containing a mixture of peat and 180g dry weight of poultry manure, cowdung, chicken manure pellet, sheep manure and horse manure. Chicken manure pellet was applied at 3.0 g pot-1 as top dressing. Mineralization pattern of the organic manures was monitored in a parallel experiment with 24 pots containing only the growth media. In this study, organic manures significantly increased plant height and chlorophyll content of leaves over the control plants. The application of inorganic fertilizer increased plant height over chicken manure and compost. In addition chlorophyll content was higher with inorganic fertilizer than cowdung at six weeks after germination. N mineralization significantly varied among organic manure sources with compost having the highest mineralized N and sheep manure the least. Plant tissue analysis revealed significant differences in plant tissue nutrient composition under organic manure treatment. Growing plants in organic manure resulted in 1.2 to1.6-folds, 1.1 to 4-fold and 1.1 to 4.1-fold increases in total N content of plant tissue at four weeks, eight weeks and twelve weeks after germination, respectively. Dry matter production by plants was also significantly increased under organic manure treatments. Organic manure application had the potential of increasing spring barley yield by 1.5 to 4-fold. Cowdung appeared to be the best source of organic manure for spring barley production.