Gardenias grow as a small tree, reaching heights of a maximum of 15 feet. They may live up to 65 years, providing deep-green foliage and small, white flowers to the landscape. Propagating gardenias is most often done from seed. As they flower continuously, there is rarely a shortage of seeds from existing plants, or you may wish to purchase seeds. The seeds are found inside small, 1-inch diameter fruits that are produced immediately after flowering.
Soak the seeds in a bowl of warm overnight. This helps soften the hard seed coat and leads to easier germination.
Fill a 6-inch diameter pot with a soil-less potting mix. Create your own mix by combining equal parts of the peat moss, compost and perlite.
Water the mix until it is evenly moist, which occurs when the water begins draining from the bottom drainage holes in the pots. Sow gardenia seed directly on the potting mix surface, then gently press it into the soil so it makes firm contact with the potting mix.
Place the pot in a warm room out of direct sunlight to germinate. Check the moisture in the potting mix regularly and water as needed to keep in evenly moist. Germination should occur in four to six weeks.
Place the seedlings where they receive six hours of bright, indirect light and keep the soil moist. Transplant the gardenia seedlings outside once they develop their third set of leaves.