this is the stuff that flower shops generally stock
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The shipping is as much as an orchid and they generally do not arrive in good condition. If you are lucky the plant can recover but most of the time they are in such a poor condition and sold in full flower putting additional stress on the orchids that it is hard to keep them alive.
These commercial orchids are not meant to survive longer than a couple of weeks in people's homes. They are not great candidates to start with, if you lose the orchid it just discourages you from the hobby which is not that hard. In hindsight a lot of my supermarket purchases were bad decisions.
The best oncidium I would recommend for anyone is a Tiny Twinkle, there's lots of different colors.
The tinky Twinkle seems to be an extremely seasonal orchid, it's available once a year it seems but not many stock it at all most of the time but that is the one you want to get.
I've thought in the past, right I can't get the one I want so I'll get something similar that is maybe a bit bigger but then you always still want the first one, usually end up finding it in the end and then you are stuck with the one you didn't really want.
It's not too bad, one can always give one away but its best to get the one you want even if you have to look a bit longer. It certainly beats getting one that won't survive.
Unfortunately the oncidium tiny twinkle is what I would classify as a commercial orchid so sold cheap in poor condition but they are pretty resilient and well worth finding one.
There are lots of oncidiums but most of them get rather big, the tiny twinkle is a hardy orchid and it stays compact but the fragrance is powerful so best of both worlds.
wichman sometimes tocks them but at the moment they seem to be out of stock:
Suchergebnisse fur: 'Tiny Twinkle' | Orchideen-Wichmann.de - Hochste gartnerische Qualitat und Erfahrung seit 1897