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Pitcher irrigation is particularly useful for horticulture in arid zones. It is of interest to see the correlation of water flow (WF) through the pitcher wall into air, water, and soil with the moisture deficit in air (MD). The pattern of WF into the three media was studied for four pitchers filled with water up to the neck, under natural atmospheric conditions and under hydraulic head (HH). WF without HH was in the order air>soil>water, the amount being negligible in water. WF under HH was also in the same order, but with a significant increase in WF. In all cases WF correlated linearly to level of dryness of the air. Hydraulic conductivity (K-s) for all the pitchers also varied in the order air>soil>water. K-s in water was independent of MD, whereas K-s in soil and air increased with MD. Thus total WF through capillary pores of the pot is due to pressure of hydraulic head only when WF is into the water medium. In air and soil there is an additional WF due to the MD in the medium. This is seen as a negative pressure or an equivalent negative hydraulic head. Copyright (c) 2013 John Wiley & Sons, Ltd.