How to Plant Curcuma Bulbs
Curcumas are flowering plants with large foliage that are native to Asia and are usually tolerate to USDA Hardiness Zones 8 to 11. Several varieties of curcumas are available, with varying flower colors. Curcumas have underground root structures that are very similar to bulbs and are often referred to and sold as bulbs, but they are not true bulbs. They are rhizomes, which are generally planted in late March or April.
Prepare your planting site, which should be in full sun. Till in a several inches of organic matter, such as peat moss or course sand, to the 12 inches of your planting site to make your soil better suited for drainage.
Plant curcumas about one per square foot and bury the bulbs only an inch from the surface of the soil. The eye--or bud--should be facing up.
Push down on the soil with your hands to remove any possible air pockets. Water the bulbs and after the water seeps into the soil, push down the soil again.
Fertilize curcuma bulbs after planting. Use about one tablespoon of fertilizer labeled 15-15-15 (or 16-16-16 for large curcuma) and a bit less for small varieties.