Torch lily prefers a humus-rich, well-drained soil in full sun. It won't tolerate a wet or heavy soil. The flowers are top-heavy, so choose a location protected from strong winds. Torch lily is hardy in U.S. Department of Agriculture zones 5 to 9.
In spring, cut back top growth to 4 to 6 inches to make room for new growth. Once the flowers on a stalk fade, snip out the stalk near the base to encourage fresh blooms. Use an organic fertilizer or compost in late fall.
The crowns need winter protection in USDA zones 5 and 6. Mulch heavily or tie the foliage over the crown for winter protection. This prevents water from getting inside the crown and freezing. To grow them in colder zones, move them into cold frames for the winter.
Kniphofia doesn't recover easily once divided, so established clumps are best left undisturbed. Propagate by removing crowns along with their attached roots from the outer edge of the clump in fall. Trim the roots and cut back the foliage to 2 or 3 inches before replanting. Space the plants about 18 inches apart. Kniphofia takes off slowly. Fill in the space between new plants with bedding annuals for a full look.
Seeds need a period of cold treatment before they will sprout. Plant them in pots or flats and place them in the refrigerator inside plastic bags for 6 weeks. Once moved to a warm location, seedlings emerge in 3 to 6 week. Remove the bags as soon as the seedlings emerge to allow free air circulation and prevent fungal disease.