Window light is just fine if it's full sun for adeniums, ideally 6 or more hours a day. It filters out UV to some extent but plants do not require it to grow and bloom. I grew many kinds of plants for more than 40 years indoors with only window light before I invested in lighted plant stands.

I over wintered all of my adeniums in south facing windows last winter myself. If you /can/ set up lighted shelving in a sunny window, even better so they can get supplimental light for more hours than you may be able to get direct sun. If you are just over wintering them without trying to make them bloom, the number of hours they get light is less important.

Here is a shot of my trays of seedlings last winter. They got morning sun through an east window, and mid day into late afternoon sun through a south facing widow. The biggest problem in winter is that it can be difficult to get more than a couple of hours of good light unless you are lucky and can stick them in a corner that has windows on both walls. The other issue is if you get a lot of overcast days, or really cold weather. You may get little quality in light and you need to be careful how much cold seeps through your windows. In the Deep South, I had a lot of sunshine in winter and not a lot of overcast with mild temperatures. So you might be fine in Houston.

Thanks Hyn! Ugh, I have very low lighting here. I have one patio at my condo and it gets maybe 4 hours direct in that window. That's all I can get here sadly. Last year I chanced the patio and lost most of my collection.

More would be better. But remember, you can also allow your adeniums to go pretty dry and dormant for the winter and not worry if they don't grow much. That won't hurt them as long as you don't water them much. The more light and warmth you can give them though the more likely you can keep them growing. LOTS of light and you may even be able to keep them flowering. Work with what you have.

Meant to say *chanced OUTSIDE on the patio* and lost them.

Thanks for your advice! Hopefully we will be in a house within the year that has an ACTUAL YARD! Haha! I can't wait.