I just received a questions about how long it takes for an adenium seed to germinate. The answer is simple if you have the right growing conditions. First, growing adenium plants by seeds is a low cost method of starting a desert rose plant collection. You can obtain adenium seeds for a few dollars (packs of 10 of 20) of various flower types. However, you need to remember until the seed bloom you will not know if the plant flower is anything like the parent plant. Only a percentage of adenium seeds will grow into plants with the same flowers of its parents.
Now back to the question. If you have fresh adenium plant seeds and you are growing them in the right condition they will germinate in 5 to 7 days. yes, I have see some germinate in three days and some 2 weeks. But 95% will germinate in 5 to 7 days if the seeds are fresh. The majority of the ones that take 10 to 14 to germinate tend to be weaker plants and older seeds. We have had great success growing adenium seeds under LED lights using tri-band and even some dual band lights. After the seedlings are over 3 months old the adenium plant seedlings are totally removed from the LED and grow under natural light.
We use standard 10×20 trays (the ones with holes/slots all around the sides) and keep the desert rose plants moist by misting them using spray bottles. Yes, we dome the trays until the adenium seedlings are 1 month old. If you have any questions concerning growing adenium plants and seeds please let me know. Have a great time growing and collecting adenium, desert rose plants.