As a desert cactus, prickly pear prefers full sun to thrive. That means at least six hours of direct sunlight per day. Indoors, a west- or south-facing window works best. Prickly pear likes dry conditions, and very little watering is required to maintain the plant. Limit your watering to every two to three weeks or when the soil is completely dry. When watering, simply moisten and don't soak the soil.