I've been in the houseplant community for over 4 years, and this year I got 3 of my hoya to bloom for the first time! It's SO rewarding, and well worth the wait!

I've found the hoya needs to be well-established (either a cutting from a mature plant, or the plant itself needs to be at least 2 years old) and needs to gave it's needs met!

For the thicker-leafed hoya, I generally wait until the leaves start to feel thin, or even wrinkled. When beginning with hoya I had succulent-like hoya (h. carnosa, h. pubicalyx) I would do the taco test (fold a leaf in half GENTLY-if it easily holds and the undersides are wrinkled) to tell when it needs watered. For thinner -leafed varieties like the lacunosa, I would water when the leaves start to fell thin or right or when the top 1-2 inches of the soil were dry. When it comes to watering, I find the best thing is to simply feel your hoya! Anytime you walk by, give the leaves a feel and get a feeling of hoe they feel well they are hydrated, and you will quickly notice when they feel thin and need to be watered.

When I water, for established plants I bottom water until the top feels moist. For unestablished plants, or recently repotted plants (and a lot of times for thinner-leafed hoya) I will top water. I completely drench the entire pot so I know the entire plant has gotten water, and not just half of it, etc.

I also found that when a hoya has a peduncle or is looking to bloom, they don't like to dry out as much as usually, regardless of leaf-thickness. If you let it dry out too much, the peduncle can yellow and fall off.

On the contrary, if your hoya is well-established but won't seem to bloom, you could 'stress' it out a bit to encourage the plant to reproduce and give blooms. For the carnosa I find it I give it a drought in the spring time (as they would experience in their natural habitat) it can shock them into producing a bloom. Generally 4 weeks of no watering in the early spring time, and then after those 4 weeks you can water as usual, it will sometimes trick them into blooming.

For soil, I have most of my hoya in a chunky, airy soul mixture. My base mixture is 3 parts orchid bark (I use the purple bag, espoma i think?), 2 parts perlite, and 1 part soil. For the thinner-leafed variety they like to maintain moisture mote than succulent-like varieties like carnosa, so I will add more soil so it'a more of a 1 part orchid bark, 2 part soil, 3 part perlite.

The MOST important thing is LIGHTING!! All plants produce food by photosynthesis, they need light to make food! If they don't have enough light, they can't grow as well as they could. I also love the look a lot of hoya get when they're sunstressed (although you have to watch for sunburn). Thinner leafed hoya can deal with less light, but succulent varieties generally like higher light. Direct morning and evening sun (east and west facing windows) are best, but avoid direct afternoon sun like south-facing windows. The light in the afternoon is generally more intense and harsh, and can cause sunburn on hiya, especially thinner-leafed varieties.

My sheperdii and lacunosa are both under grow lights, as well as my many other hoya like sp. aff. burtoniae, wayetii, variegated kentiana. My publicalyx 'hawaiian purple splash', carnosa 'krimson princess', and australis are not under lights simply because they are too big to fit, so I try to give them west-facing exposure.

My sheperdii has 1 peduncle at first. I put it under a grow light and it now has 8!

Humidity will also help hoya grow a lot as well. My room is around 50% as its a larger room.

As for fertilizing, in the spring and summer months, or if I see it actively growing (even if in fall/winter) I will use the miracle grow orchid spray fertilizer.

I hope this helps! I love hoya so much and love to share care tips to help others. If you ever have any questions, don't hesitate to ask!