Pitaya is a hemiepiphytic cactus native to tropical rainforests of Mexico and Central and South America little studied in Brazil especially in relation to light intensity and fertilizing. In this way, an experiment was realized in 2007 aiming to evaluate the initial growth and development as a function of light intensity and organic fertilizing. A complete randomized blocks design was adopted with treatments distributed in a factorial arrangement 5 x 3 referring respectively to organic fertilizing levels (0, 5, 10, 20 e 30 L of bovine manure plant-1) and light percentage (0, 50 e 75% of shade), with four repetitions. Stem diameter, plant height and length of the secondary shoot were evaluated weekly, instead of shoot and root dry mass and shoot fresh mass were determined at the end of the experiment. For week variables, the respective week increases were measured. For pitaya cultivation it's necessary a covering system with nets and those with 50% or 75% of light intensity should be used. The dose of 20 L plant-1 of bovine manure could be adopted as a quantitative for preparation of pitaya caves under soil and climate conditions of Bom Jesus, Piaui State, Brazil.
Hylocereus undatus; bovine manure; shading
