Late season Catasetinae problems
 

Seems like there's always more to be learned about this group of orchids! I've had these 2 since February, and think I did ok in my first growing season with them (at least one of them).

Now both of them have issues. The first one developed a large bulb and did very well. But when I was treating it for spider mites last week I noticed that there was a black/brown spot developing near the tip of the bulb. Should I be worried about this?

The second plant (Clowesia Rebecca Northen x self) never grew well so has a very small bulb. The odd thing I noticed is that it has already started a new growth. What do I do about winter rest? Rest it anyway and the new growth dies, or continue watering? (plant is still a year or so from blooming size)

I don't think the brown spot is an issue - mine develop these and don't cause any issues. As for the new growth, I had two small catasetums last year that did the same - I continued watering through the winter and they did just fine - one is in spike now so didn't set it back at all.

I suspect if a new growth is made at the proper time of year, but doesn't develop very well (I have a lot of experience with this) the plant tries to make more growth to compensate. I think that is happening with your plant.

Photos I see from good Catasetinae growers show young plants with 5cm tall previous years' growths making 25cm tall growths in good conditions.

Thanks for the help! These are so different from my other plants that I feel like I've learning how to grow orchids all over again.

I'm glad to know that the brown spot is normally nothing to worry about as I'd hate to lose such a nice bulb to rot even before seeing some flowers!

Ya, the brown spot doesn't worry me.

However, the moss in the Clowesia pot looks pretty loose. Is that true? Could be the reason it hasn't grown that well. The moss should be pack in very tight so it doesn't stay sopping wet. I'd let the Clowesia get crispy dry until the new roots are 4 inches long. Then water as normal and keep temps above 55 degrees.

You might be on to something with the moss. When I got them, I simply pulled them out of their plastic pots and put them in same size clay pots. Since the sphag was fresh looking, I was advised here to not repot them. The big plant has well packed sphag throughout, while the small plant (just checked this one, it slipped out of the pot rather easily) has a some packing peanuts, then a rather thin layer sphag, which isn't super loose, but not tight either. So I think the top half was staying wet, and the bottom half dry....