Pua Aloalo, the yellow hibiscus, is native to the Hawaiian islands and the state's official flower. It evokes images of soft trade winds and sparkling blue seas. Although the hibiscus is a tropical flowering plant, it is grown, and babied, even in the colder climates of Canada. Officially, however, hibiscus is hardy in USDA zone 8 and higher.
Locate the seed pod on your hibiscus plant. This will be located in the base of the flower after the petals fall off. Once the pod turns brown it will open and you can then gather the seeds. Sometimes the pod will open unexpectedly, so place a white sheet of paper or bowl at the base of the plant to catch the seeds.
Soak the hibiscus seeds overnight in water.
Nick the outer covering of the hibiscus seed slightly with a razor blade or small nail clippers. Just make a small opening in the seed jacket.
Pour the seed starting mixture into the seed tray until it comes to within 3/4 of an inch to the top of the tray. Water the soil well and allow it to drain.
Plant the seeds 1/2 inch deep and cover lightly with soil.
Place the seed tray on the heat mat and set the temperature to 80 degrees. Do not over-water the soil during germination or the seeds may rot. Keep the soil moist but never soggy. Your hibiscus seeds should germinate within 4 weeks.
Transplant the seedlings when they reach 4 inches tall. Depending upon the weather, the seedling can be transferred to the garden or planted in a gallon pot. If you are planting directly into the garden, introduce the plants gradually by leaving the seed tray outdoors for 3 hours a day, for 2 or 3 weeks. Then, gradually lengthen the time they spend outdoors prior to planting in the ground.
Fertilize the hibiscus seedling, after transplanting from the seed tray, with a diluted solution of 20-20-20 fertilizer.