Dormant Or Not?
I've read the response to one of my earlier questions regarding a Begonia cutting. Unfortunately it did not cover my particular problem. My cutting is from the winter Reiger Begonia's. After propagating if from one of its leaves, it grew to about 2 to 3 inches high, which forced me to repot in regular small pot. I give it exposure to grow lights for now over a month and although it still looks like when I repotted it. If it's a winter variety as its often described,why doesn't it show any growth? I hesitate to fertilize based that if it's in a semi dormant stage? But how can it be in a dormant stage if its known to be winter growing type?
Certified GKH Gardening Expert
Unless you are giving it a dormant stage, on purpose, it will not go into dormancy indoors while under lighting.
If you are certain that the cutting is well rooted, and was established when you transplanted it, then it will be time for fertilization.
The term "Winter Begonia" will describe the flowering habit. They will set flower, usually once done with their vigorous growth for the year. This is at the end of their yearly cycle. They should not be actively growing at this time, in nature. Since it is indoors, you will have to force dormancy each year.
Your Begonia is a hybrid that will be treated more like the Tuberous Begonia side of the lineage.
Here are a couple of articles for caring for these: