Debora, Seedlings are hungry babies that can grow quickly. I water and feed mine like I would petunias or even broccoli. About five to eight months to bloom time, some are precocious, some slow. Grown "hard", which means dry and not fed much, some don't bloom for two years or more. I don't do that!
I am beginning to believe Adeniums have ages like humans: baby, teenager, adult. Babies are up to just before their first blooms. They want to grow! Then they bloom and perhaps slow down a wee bit, then adults shortly afterward, with blooms becoming stable. The first blooms might change some the second and third time the plant blooms.
Where I live, the coldest nights are 67 or 68 degrees Fahrenheit, 20 degrees Celsius. I water and feed all year around, and they grow some leaves, bloom and then grow some more leaves. A constant cycle for most of them.
I'm beginning to grow mine like a nurseryman in India. He leaves the caudex under soil until the plant is three years old, repotting occasionally. This makes for huge caudices in the shortest time.
First day for this bloom, but the sun faded the dark, and now it's more of a brick red.
