Zantedeschia hybrids - Growing calla lily Indoors: Light: Bright, indirect light during the growing season. They dislike direct sunlight. Water: Keep potted and blooming plants constantly moist. Give it a brief resting period, then repot in late winter into fresh soil and begin watering again to encourage new sprouts. Temperature: On the warm side during growth and blooming. Soil: A lose, well drained potting mix. Fertilizer: Fertilize during the growing season with liquid fertilizer.