When to repot various orchids?

[ChatteringCat]

I have a few orchids that likely need to be repotted, but I have been hesitant to do so for various reasons.

1) The white and purple IKEA phal: This one was purchased in bloom, as many are. Last September, I believe. I figured I would wait until the blooms fell off, and then repot. I am still waiting. The original blooms started wilting around mid november, but the same spikes started extending further from the ends, with new buds. It actually looks quite odd now, since the orignal blooms are gone, leaving bare spike, but the spikes extend further now with many blooms pointing every which way. No sign of them wilting yet, and a NEW spike was sent up and it is already at least 8 inches long. I am afraid it will bloom again before the current flowers drop. It's new leaf is also a good inch and a half longer than any previous leaf. I suspect this phal likes it here. Why it needs repotting: The roots are pretty crowded. Over 50% of the clear pot inside is covered in roots (also with new growth) and roots are growing through the bottom holes and sending up aerial roots reaching away from the pot. Also I got it from IKEA. Who knows what is in there. I am mostly hesitating because it seems pretty happy. When is the right time to repot this? Is it safe to wait until there are no flowers? Will there ever be no flowers?

2) Dendrobium Nobile (also IKEA): This one is planted in some kind of coconut husk or moss maybe? I have no idea, which is why I want to repot. It holds its moisture VERY well. It is sending up its third cane currently, and other than accordion leaves at the top of the second cane (I really thought winter rest was a thing... I guess not?), it seems healthy. There are little nubs on the second cane, but I am not sure what they are... flowers or kekis? It is also sending up aerial roots which are growing fast. Why it needs repotting: I don't know what is in there. Also, I have no idea what the medium is. Do I try to find a similar media to pot it in, or do I use straight bark like my local orchid nursery does? It also seems happy right now, but I don't know what aerial roots mean in this case.

3) Two different cattleyas (unknown hybrid and Hawaiian Splash) from local nursery: These are both having alot of new root growth over the side of the pot. The unknown hybrid (seriously, the language barrier at the local nursery is annoying, I need to learn better German) also has what might be a new bulb hanging out over the edge of the pot. I am hesitant because these both have a "healthy" green moss growing on the top of the media. Is this there for a reason? I assume the cute little clovers are not something I want to keep, but what about the moss? Questions: What type of media should I pot these in? Straight bark, a Seramis / bark mix, or something else? Do I save the pretty moss?

4) Oncidium Sharry Baby (from local nursery): Quite honestly, I forgot I hadn't repotted. It sent out two new bulbs close to the pot edge that are about half grown. I am not sure it needs repotting, other than the fact I don't know what is in there. It is potted in a large bark mix, and seems happy. The pot isn't clear though, so I don't really know about the roots. It has sent up some aerial roots.

5) Vanda (random hybrid): This one is in a terracotta pot with holes all over the pot, and large bark pieces. There are actually two in there, a big one, and a little one (with a plastic pot in there someplace. I was SURE I would kill this one, so I wasn't overly worried about when this would need repotting. I am pretty sure it doesn't now. This one did not in fact die, but it had a quite interesting adjustment period. The nursery told me I only had to water it once a week since it was in a pot. I quickly realized that was incorrect, and I managed to water it more often (a good long soaking of 15 minutes or so every second or third day), but not before large sections of the roots outside of the pot went crunchy. I have no idea what the roots in the pot look like. I trimmed off the crunchy bits recently, and within a week, there were new roots coming off the previously damaged ones. The next week, a new aerial root made its way through the stem about an inch above the bark (and the lower two leaves), and a flower spike went up. The spike is now about 4 inches long, and another root is coming up out of the stem about a quarter inch higher than the other new one, but on the other side of the plant. Questions: Again, I am pretty sure I don't need to mess with this one, but what do the new roots mean for the plant? Does it mean anything for the leaves below the roots? The pot also smells kinda like algae... is that bad? I think there is algae on a visible root also.



So, that was alot. I haven't actually had any major orchid disasters yet, so I may be a bit timid waiting for the first one to hit. Advice is really, REALLY welcome. I am generally trying to go with messing with my orchids as little as possible so I don't kill them with too much love. Almost everything I have repotted (a phal and several oncidiums) are in the Seramis/bark mix since that is easy to find locally. Everything so far seems pretty happy in it.