Can Phalaenopsis aerial roots be buried in sphagnum moss without being prone to dying?
Those aerial roots that Phalaenopsis sends out from beside its leaves - can they actually be buried in sphagnum moss? It always feels awkward to just let them dangle outside, but I'm also afraid that burying them might end up killing the plant.
First, you need to understand that Phalaenopsis aerial roots are not ordinary roots. If you look closely, you'll find that most of them are green or grayish-white, and their surface has a slight fuzz. All of this serves a special purpose. Exposed to the air, these roots can directly absorb moisture and nutrients from the air and also help the plant "breathe," just like Phalaenopsis's own built-in "respiratory system."

So can they actually be buried in sphagnum moss? The answer is not absolute; it depends on the situation. If the sphagnum moss in your home is always soggy and drips water when squeezed, then it is truly not recommended to bury them. Aerial roots are used to air circulation. Stuffy inside moist sphagnum moss, they are like a person whose nose is covered, and over time they will certainly rot. A neighbor once made this mistake, thinking the aerial roots looked bad outside, so they stuffed them all into the sphagnum moss. As a result, in less than half a month, the roots turned black and slimy, and the whole plant wilted badly.
But if you control watering especially well and the sphagnum moss always stays "moist but not wet," then burying them is not a big problem. Experienced flower growers have tried gently burying aerial roots into loose sphagnum moss. As long as you do not press it too tight and leave gaps around the roots for air, it can instead make the roots grow stronger. However, there is a precondition: after each watering, promptly pour off the excess water and do not let water accumulate at the bottom of the pot. 
There is also a little trick: for a Phalaenopsis just bought home, if the aerial roots have already grown very long, it is best not to disturb it first. Let it adapt to the home environment first. Rashly burying the aerial roots makes the plant prone to stress, and the leaves may turn yellow. You can observe it for a period first, and wait until you see signs of new growth on the aerial roots, such as tender white root tips emerging, before considering whether to bury them.
Phalaenopsis is not that delicate, and aerial roots dangling outside are not a bad thing. Sometimes they find their own place and, along the edge of the pot, drill into the sphagnum moss. This shows that the environment is suitable, and we do not need to help manually. There is no need to insist on "uniform neatness." As long as the flower grows vigorously, aerial roots exposed outside are instead a sign of health.

Overall, whether aerial roots can be buried in sphagnum moss depends mainly on watering and ventilation. Grasp the principle of "better dry than wet," keep the air circulating, and even if buried they can still grow well. If you are not confident, then just let them stay freely.