| I would re-pot into the pot one inch larger even thought the plant is still growing over the side.
If you go up two inches you risk rotting the plant as it will hold a lot of water and you may lose flowering this year while it grows into the pot.
Use the smaller size and re-pot again after the next blooming. At that time you can judge whether the roots have grown enough to fill the larger pot.
Oncidium Alliance plants can do well in very small pots. I have some plants 20 inches across that are still in 4 inch pots.
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jerry  |