Flower spike stopped growing
 

I have a Wilsonara 'Tiger Brew' that started a flower spike a couple of months ago. The spike grew to about 8 inches, and then stopped growing. Near the top of the spike, there are a couple of small buds about 1/4 of an inch in diameter. These buds haven't grown any larger in weeks. This orchid is potted in a fine bark mixture, and it's sitting in a east-facing window. The temp gets into the low to mid 80s on hot days, and down into the 60s at night. I water it twice a weak, fertilize at 1/4 strength once a week, and try to maintain at least 50% humidity. The plant sits fairly close to the window. What could be causing this flower spike to stop?

Do you have an orchid show coming up? Just kidding. You see, my orchids always seem to avoid having their buds/spikes open for the shows. :)
Some orchids are very, very slow to open their buds and even seem to take breaks. I have a few that are in bud or are spiking and it seems to be taking forever. If this isn't the case, and the roots are healthy, changes in light and temperature can have an effect. It seems as if the temperatures are fine but perhaps the changing of the sun's angle or the shorter number of daylight hours has something to do with this. I know many of my South windows are just starting to get decent light.

I wouldn't worry. I've had orchids take a break. As long as the spike and buds still look viable, just be patient. If they turn shriveled and brow, well you know they didn't make it. I don't know what makes them do this, but it seems to right itself eventually.

So patience, grasshopper.

Having the same issue except mine started then stopped almost immediately so theres just a little green beginning of a spike waiting for idk what to continue growing. I think it got stage fright when I noticed it...

I find my Wilsonara a water hog..so I give it daily watering, and it seems to help it push those blooms faster.

I find Oncidium spikes to be very slow growing compared to some other orchids. I have stepped up the watering on mine since a friend is having great success with multiple spikes after accidently leaving her Onc. plants sitting in dishes of water all summer. She said they just seemed to love it! I'm not going to risk doing that but I have been watering more!

I water my oncidium daily of course I grow it next to my south east facing window with windows open up and here in socal, temp is so hot here even in late sept now. We just have tripple digits past week. My oncidium is in spike as well...been in spike for a month already..now buds barely forming...so yea, they are slower grower when it comes to spike.

When it is really triple digit hot here, I also do that, make my Onc sit in water..they love that a lot! My Wils also has a bloom spike right now, it's 2nd flush for this year.

But temps are so much nicer now..very comfortable..so getting some bloom spikes in other orchids too. The difference a good cool down makes fromthe previous searing summer.