A greenhouse experiment with parsley was conducted to investigate the effects of organic liquid fertilizers on biomass yield, photosynthesis, root zone pH, electrical conductivity, and nutrient concentrations of plant tissue and growing medium. Limed peat with 20 kg m^-3 composted chicken manure was used as the growing medium. Four organic fertilizer treatments based on chicken manure extract and lupin sap were compared with conventional inorganic liquid fertilizer and no liquid fertilizer (only solid fertilizer). Chicken manure extract resulted in a higher biomass yield than lupin sap (6.7 g dry matter compared with 5.8 g) but lower than inorganic fertigation (8.4 g). Photosynthesis was not influenced by type of fertigation. Growing medium pH was between 7.4 and 8.5 in all organic treatments and one to two units higher than in the inorganic treatment. Electrical conductivity was highest in the lupin sap treatment. The root zone concentrations of NH₄, K, Cl, and Na were found to be higher in the organic treatments. Inorganic fertigation, on the other hand, resulted in higher concentrations of NO₃, Ca, and Mg. Concentrations of P and most of the micronutrients were at deficit levels in the lupin sap treatment. The addition of extra micronutrients to lupin sap increased the tissue concentrations but not the biomass yield. Among the organic treatments, chicken manure extract showed the most favourable root zone conditions and biomass yield.