Now that we have touched pot, soil, and watering, it’s time to talk about light and humidity. Hoya curtisii will grow well in full sun or very little sun. It is pretty adaptive. I flowered this plant the first time after having it exposed to full sun out of doors for a full summer. The second and third time it flowered just as the days were beginning to lengthen in late February/Early March indoors in a northwest window with almost no sun.
There is no doubt that Hoya curtisii grows best in high humidity, but it will muddle along with relative humidity as low as 40%, but expect a lot of dried out growing tips. My plant lives year around now in my house witch gets pretty dry in the winter time. I think think this Hoya would like to live in a bathroom where it would get extra humidity from people taking showers.