How to Plant Gardenia Flowers
How to get seeds for gardenia.
Certified GKH Gardening Expert
Gardenias are best propagated though cuttings rather than seeds, and this article can help you with that: https://www.gardeningknowhow.com/ornamental/flowers/gardenia/propagating-gardenias.htm
However, if you would still like to try growing gardenias from seeds, then here is more info: https://www.ehow.com/how_7548774_grow-gardenias-seed.html