A greenhouse experiment was set up to study the effects a synthetic conditioner "Bocashi" Terracottem® (a mixture of water absorbent polymers, fertilizers, root growth stimulators and lava) at two doses (TC1 and TC2) and an organic conditioner (BK), on the production of above ground and root biomass of a green pepper, Capsicum annuum L.,crop in a sandy soil. Two irrigation doses were applied to maintain the soil water content either at 100% or 80% of its field capacity (FC). The efficiency of water use was evaluated in terms of consumption of water after 28 days of cultivation in relation to (1) the total volume of applied irrigation water, (2) the above ground biomass and (3) root biomass. It was obvious that for all treatments more water is needed to maintain the soil moisture content at 100% of FC than at 80% of FC. The highest above ground biomass production was obtained with the highest Terracottem dose (TC1) at both soil water contents. No significant differences were found between the two irrigation doses. TC treatments resulted in higher root biomass production than BK at the highest irrigation dose. The lowest levels of water consumption per unit biomass and unit root biomass were obtained in the TC1, BK and TC2 treatments. Also, no significant differences for above ground and radical biomass were found between irrigation doses, thus crop vegetative development was not affected when submitted to water stress.Torres et al. Agron Trop. 2008