image by Lori Downing/sxc.hu
Cannas are often referred to as canna lilies, though they aren't actually lilies. Large blooms and lush foliage are the hallmark of most store-bought and bulb-grown cannas. Growing from seed is more of a gamble, as the flowers rarely look like the parent plant and may be weak with poor blooms. They also may put forth an exciting bloom unlike what you expect, but one that is attractive nonetheless. Start with seed from healthy plants or a reputable dealer to give your seed-grown cannas the best chance to thrive.
Scratch the seed coating with a nail file or fine-grit sandpaper; if you skip this step, the seed will remain impervious to water and won't grow. Place the seeds in a bowl of hot water and soak for one to two days to finish softening the seed coat.
Choose a 6-inch diameter pot with drainage holes on the bottom. Place a tray beneath the pot to catch the excess water.
Fill the pot with a rich potting soil or make your own by mixing 1 part peat moss to 1 part compost. Fill to within 1 inch of the rim of the pot.
Plant two to three seeds per pot. Sow each seed 1 to 2 inches apart and a 1/2 inch beneath the soil surface.
Water the soil until it is moist but not soaking wet. Keep the soil evenly moist at all times and empty the drip tray of any excess water daily.
Place the pot in a plastic bag, then in a warm room with indirect sunlight. Wait for shoots to appear about seven days later, then remove the bag and place in a sunny window.
Transplant outdoors into a rich, well-drained garden bed with full to partial sun after all danger of frost has passed. Keep the soil moist but not soaking or the bulbs will rot.