Adeniums (Adenium obesum) are more commonly known as desert rose. They are perennial growing plants that are native to regions in east Africa. In their native habitat, adeniums will grow to 6 to 10 feet tall. They produce showy, 2- to 3-inch-wide tubular-shaped flowers that come in pink, purplish-red and white. Plan on planting adenium seeds in early spring, from March through April.
Separate the adenium seeds from the delicate feather-like hairs that are attached to each seed. Place the seeds onto a sheet of paper. Dust the seeds with a fungicide made specifically for seeds. Read the instructions on the label of the product in regard to how much fungicide to use. Using a fungicide will help prevent the seedlings from dying from a fungus disease.
Sterilize a soil-less seed-raising mix, if the label does not state the product has been sterilized. Soil-less seed-raising mix contains vermiculite, perlite or peat moss. Place the seed-raising mix into a metal bowl, or shallow metal tray. Preheat an over to 300 degrees F. Place the bowl or tray into the oven for 30 minutes. Let the mix cool off completely before using.
Scoop in the seed-raising mix into planting packs or into 3-inch plastic pots. Pack the mix down using a metal spoon or your fingers.
Transfer each of the planting packs, or 3-inch pots, into a shallow watering tray. Pour approximately one quart of water into the tray and allow the soil in the pots, or planting packs, to absorb the water until it is visibly well moistened.
Plant two to three adenium seeds into each cell, if using planting packs. Plant two seeds per pot, if you are using 3-inch-wide planting pots. Gently push the seeds into the soil to a depth of 1/8 inch to ensure good seed-to-soil contact. Sprinkle approximately 1/4 inch of the seed-raising mix over each of the adenium seeds.
Place the tray in a location that will provide a temperature of between 80 and 85 degrees F. Provide approximately eight to 10 hours of indirect light each day. The seeds should be kept moist but the medium should never be allowed to remain soggy. Germination of adenium seeds will begin in about seven days at these conditions. If the temperature drops below 80 degrees F, germination can take longer.
Thin out the adenium seedlings when they are approximately 1 inch tall. Snip off at the soil line all but the most hardy seedling in each cell of the planting packs, or 3-inch pot, to leave one seedling in each pot or cell.
Transplant the adenium seedlings in about 30 days, or when each seedling has at least six pairs of leaves. If you live in a growing region where the winter temperatures drop to 35 to 40 degrees F, transplant the adenium seedlings in containers so you place them in a protected area when needed, as suggested by John McLaughlin and Joe Garofalo with the the University of Florida.