It takes up to three months from planting to full bloom. So tubers should be started indoors at least a month before the last frost date. Set tubers 3 centimeters apart in shallow pots filled with moistened potting soil. Water thoroughly only once to stimulate growth, but do not let the soil dry out completely.

Once the sprouts are 2 to 5 centimeters long, re-pot the tubers in 15-centimeters pots, or their permanent containers. To produce fewer, but larger flowers, pinch off all but a few of the young stems. For a bushier plant, allow all the buds to develop into stems.