Oncidium repot question
 

Hi I am pretty new at growing orchids so I was wondering if repotting oncidium orchids always causes them to go into shock.

I have two that I have repotted and on both of them the bulbs have gotten really wrinkled even though they had good roots.

One of them had hardly any dead roots and the other had quite a bit that I had to cut off. Both of them seem to be doing the same as far as no matter how much I water the pseudobulbs don't seem to want to plump back up again.

I took them both out of the moss they came in and put them in a bark and moss mix so the roots would get more air.

I am wondering if I am possibly doing something wrong. Maybe I was too rough removing the old medium because I did spend a lot of time on one of them getting all the old moss out of the roots.

Thanks

It is almost always best to repot as new roots are beginning to grow. Most orchids only make new roots from the new, developing growths. Some orchids develop the new growth quite a while, and make new roots when almost mature. A few completely mature new growths and even flower, then make roots from those growths.

But older growths rarely make new roots. So if you repot at the wrong time and damage a lot of roots, the plant will struggle to take in adequate water until it can make new roots. All repotting damages roots, even if you are very careful.

Oncidium hybrids usually make new roots around the time new growth develops. The weather is warming up, so there is a good chance your plants will make new growth, and new roots, before long. Once they start making new roots, they will be able to take up more water, and should look better.

You might have cut off healthy roots. This is one reason I almost never cut off roots when repotting. Most of the time I really can't tell what is good and what is bad. Especially with Oncididums I would recommend against this, unless they are obviously black and slimy.

Before your plants begin growing, make sure the roots don't completely dry out. If you're using new, large bark, you might be able to water every 1-2 days. When they begin making new growth be sure they don't dry out. If new leaves get horizontal pleats the plant isn't getting enough water.

I have noticed that changing Oncidiums from moss to bark is harder on them than it is on most other types of Orchids. It takes them a little longer to get adjusted to their new medium. I think it is the right thing to do to pot them in bark rather than moss, but when I do that, I almost always notice some shriveling of the pseudobulbs. The plant will need to be watered much more frequently in bark than when it was in moss, so adjust your watering practices accordingly. During the summer when my plants are outside, I water the Oncidiums every day. Once the new roots get established in the bark, the plant will be just fine.

While you are waiting for new roots, if it is possible you shout leave the plant outdoors in the shade during prolonged rainy spells. Few things re-hydrate an orchid like a good soaking rain.