This study aimed to determine the gas exchange and the chlorophyll content of green pepper plants under doses and times of application of bio-fertilizers based on manure and enriched organic compost. Two experiments were carried out simultaneously with applications of bio-fertilizers prepared from manure and enriched organic compost, one using cattle manure (CBF) and the other sheep manure (SBF). For these, four doses of biological fertilizers (100, 200, 300 and 400 dm³ ha-1), three application times (0, 30 and 60 days after transplantation - DAT) and absolute control, referring to the absence of fertilization, were used. treatments. were arranged in a randomized block design, totaling 13 treatments. The variables evaluated were: the relative chlorophyll a, b and total content; liquid photosynthesis (A); stomatal conductance (gs); internal CO2 concentration (Ci); instant carboxylation efficiency (iCE - A/Ci); transpiration rate (T); intrinsic water use efficiency (iWUE - A/gs); and water use efficiency (WUE - A/E). Gs, A and T, showed significant effect at 60 DAT with the application of SBF and Ci at 30 DAT with CBF. The dose of 400 dm³ ha-1 of SBF provided greater gas results, and the doses of 200 and 300 dm³ ha-1 of CBF promoted a greater Ci, greater stomatal conductance, greater liquid photosynthesis and better water use efficiency, which results in a greater plant fresh weight at the time of flowering induction.