Oncidium PBs growing smaller?
 

I've had this Oncidium " Twinkle" for a year now, and it's grown 4 new pseudobulbs in my care. They started out smaller, but nothing that seemed too alarming. I was told that this was because it was adjusting to my environment. The new pseudobulbs are around they size of a Canadian dime and I'm a bit worried.

https://farm4.staticflickr.com/3837/...d6805b835f.jpg
IMG_1569 by Dante1709, on Flickr

I give it plenty of sunlight (maybe just a bit more than it can take, since the leaves are a bit on the yellower side, but still healthy), decent humidity (40%+), as well as what I believe is enough water and fertilizer. I give them the morning inside and I let them outside in the shade when it's warm, and often, this is a quick temperature change.

I've done a quick google search and I've found things about plants slowly dying when this happens, but I want to find WHY this would be happening, if there's anything I can do to help it..etc

It's possible that the plant was grown in ideal commercial greenhouse conditions geared towards producing a huge healthy flowering plant in the least amount of time possible. Your conditions are different and the plant will grow at a slower, smaller pace. As long as things look green and pseudobulbs are plump, I don't think you have to worry too much.

My $0.02...

Its a little hard to see, but your plant looks pretty healthy. Do you see new root growth as the new pseudobulbs mature?

With most oncidium alliance the pseudobulbs don't reach the full size until the new growth is mature. With good light each subsequent new growth should show a size increase from the previous, limited by the plant's genetically determined size.

How long has the plant been in it's current pot and media?

At least 5 months ; I haven't really written it down (although now I know I should have). The potting media was less than ideal, since it was small-graded fir bark intended for reptiles, but the plant seems to be sending out roots.

I disagree that your plant is slowly dying. I think it is the exact opposite. You must look at things in context, and you must have some experience under your belt to know the difference between a plant that is developing, and a plant that is in distress because the signs are oftentimes very subtle and can be difficult to verbalize and tell apart. Proper diagnosis comes in context of the situation, not out of it.

Your Oncidium Twinkle 'Fragrance Fantasy' looks fine to me.

As Oscarman had mentioned, the pseudobulbs do not reach their full size potential until the growth is fully mature. The size of the pseudobulb at the time that it is first developing will not be how large it ends up being. That new developing pseudobulb could end up being slightly larger to significantly larger than some of the preceding ones.

Originally the plant was sold to me as Onc. twinkle "Pinkie" with the tag saying "Red". Either way I doubt the name matters that much.

I'm glad to know that there isn't anything horribly wrong with my plants and I hope I get another blooming spike.

I suspect underwatering is to blame.

If you do not give them enough water during the growth phase, then the pb will always mature smaller than they would otherwise.

I'm thinking the same thing. I have a Twinkle I think it is a Fragrance Fantasy, light pink, mine just say's Onc. Twinkle. I have had the poor thing for years, it bloomed every year, heaven only knows how as I was always under watering it. The blooms never lasted long as they would fall off.

I finally found this forum re-potted it and found out I was not watering enough. A lot of my PB were on the smaller size but last year after I took better care of it, it put on such a nice show. It had 4 PB 2 with 2 spikes 1 with 1 spike and one small one that didn't bloom, I am now in love with it.

It now has 5 PB I am still waiting for one to see if it will have only 1 spike as I can barely see the first one, but I do have 4 that have 2 spikes. The PB on the first spike that didn't bloom last year and started first is just now getting bigger that the one before but all the others, and they are spiking are still not as big as the ones before them. So give them some time. Your plant looks much younger than mine. I can't wait for this years blooms.

Here is last years.

I notice you moved it from fine bark to what looks like a chunky medium bark. I actually pot many of my Onc. type in fine bark. If they have fine roots (which Twinkle does), then I usually give them a finer medium. So it may still be adjusting to that and water could be an issue. But as others mentioned, it does look quite healthy. If you aren't getting wrinkled leaves as they grow, it likely isn't suffering too bad from lack of water.

Your Onc looks a-okay to me too! I also use fine bark for my Onc, seems to make it easy for the fine thinner roots to latch on. And I give my Onc lots of water..they love to drink, especially this summer. Well, my temps are different though, we hover in the mid to high 80's and higher, so they go so thirsty here a lot.

Give it time, it may just be still adjusting.