My big oncidium—or maybe it's something else?—has survived multiple repottings and is now about a foot in diameter. It's not "well grown," in that it develops brown and black spots, loses yellowed leaves, etc., but I've had it for many years, and its annual blossoming is spectacular. But now it has a few areas where roots are developing above the potting medium. Should I tuck some bark in around them? Try to detach and start new plants? Ignore? And what besides neem spray might combat the spots and yellowing? Thanks!

Next time your Oncidium needs repotting, you can divide it. In the meantime, don't worry about those above ground roots. Most orchids, including Oncidiums, are epiphytic so their roots don't need to be covered at all.

Your orchid (what I can see of it) looks very healthy and happy. Neem won't cure spots or yellow leaves so I personally wouldn't be using it. Old leaves get yellow and fall off as new leaves and bulbs grow. Spots are just spots.

Thanks, Daisyl/Daisy I/? Daisy 1? I'm glad I don't need to do anything. Neem seems to deter further spotting of the leaves, at least for a while. One issue may be overfertilizing, as I see lots of ugly dark leaf tips. (I cut them off, making blunt ends that aren't pretty either).

When you fertilize your orchid, cut the package mixing rate by at least half, maybe even more. Fertilizer is overrated and, although plants needs some food, they don't need as much food as the makers of fertilizers would like you to believe.

You can get rid of some of the excess by running water through the pot for a few minutes. I fertilize my orchids twice a year with a slow-release fertilizer.

Yellowing leaves is senility.
Spots are typical with plicate leaves orchids. Not to worry.
You can repot it again or divide it into several smaller plants. Roots coming out of the pot are normal and of no real concern.
You sound like it blooms often so don't worry since it looks real healthy.

Thanks to both of you. It seems that I've been lucky to keep this orchid alive for so long, as I am overfertilizing (weekly, weakly late winter to midsummer) and not rinsing through very thoroughly. Senility I understand--I have a touch of that myself.

Thanks again.

No, you haven't been lucky! You in fact have done a good job with it. Look for us in the Orchid Forums if you would like.
I would just like to let you know that just keep doing what you have been doing. "If it ain't broke, don't fix it!"