This research was carried out in order to study the effects of three rates of GA3 as a preplant rhizome immersion [0 ppm (control), 50 ppm and 100 ppm] and three forcing environments [no heating (control), air heating and air heating + basal heating] on the flowering of white calla lilies. Rhizomes were planted in May and plants were grown in pot in a plastic greenhouse. In 0GA3 plants under natural thermal conditions flowering started at the end of February. Application of GA3 reduced the time to flowering (-100 days) and increased flower productivity compared to the control (20 vs 18 stems m-2), but had negative effects on flower length and stem diameter. Thermal control determined a 4-week earlier flowering only in plants from non treated rhizomes while did not affect the earliness in pre-treated plants. Air heating increased cut stem production from 17 to 20 stems m-2 and reduced the stem length compared to the no heating control, whereas the use of basal heating did not result in differences in stem productivity and quality.