Repotted Brassia (Oncydium) with few roots left

[Maria José]

hello ,
I am quite new to orchids. I have just been growing Phalaenopsis for a year now. I keep all orchids indoors as I live in Dublin and the weather is cool in general. Last summer I got this Oncydium 'Brassia".

It was in a small grey pot, and two weeks ago I decided to repot, it. I put it into a bit bigger, transparent pot, with holes on the sides. Next, I got rid of all the dead roots and I was left with just a few ones.
I put it into a mix media (medium sized bark and bits of red clay) to which I added Spagnum moss. I read that this material would help with root development. I probably overwatered it and it happened to be raining a lot outside, so the plant got some spores growing on the roots. I had to repot it again, got rid of the Spagnum moss and added a tiny bit of perlite to it. My question is: is trying to anchor the plant with skewers enough? should I put it back into the small pot? The plant looks healthy to me. Regards,

[estación seca]

Welcome to the Orchid Board!

Oncidium is a genus of orchids. There are other genera closely related, and they may hybridize. Brassia is one such genus related to Oncidium.

This kind of plant likes plenty of water, but also plenty of air at the roots. Most orchids with genus Brassia in the ancestry like warm growing conditions, and often do well in the house. What are your outdoor temperatures?

They only make new roots around the time a new shoot is forming. Sometimes the roots start just before the shoot, and sometimes just after. Before then you will need to keep it properly watered and prevent more roots from rotting.

Use a pot big enough to hold the base of the plant with 1-2cm / 1/2"-1" extra room all the way around. I would anchor the plant with something. When new roots grow they may be damaged if they move against the potting medium.

If you leave it outside in the rain, use a potting mix with very large air spaces. If you grow it in the house, and control watering, you can use something more moisture-retentive.

Water it so it never gets completely dry, but don't keep it constantly wet.

When it begins growing the new shoot and new roots, it will probably need more water.

Good luck, and let us know what happens.

[Maria José]

Hello Estación seca,

Thank you for the reply!
Oncydium and Brassia were the only words written on the label of the plant.

Today is hot and sticky 23ºC and 70% humidity. Yet, last week it was pretty cool. I read orchids shouldn't be moved around and growing them outdoors all year round here is not an option. Winters are cold.

There is a new pseudobulb and one tiny root had appeared after the new growth. I decided to repot it because the plant looked too big to me for the original pot, otherwise I would have had to wait for a whole year.

I am not sure what to use instead of Spagnum moss to help with the roots.

Regards,

[estación seca]

Fortunately Oncidium hybrids are mostly easy to grow in homes. Most will make new growth multiple times per year. The sequence is: Flowering finishes. There may be a short rest period, or it may grow immediately. A new growth develops, matures and flowers. Then another growth starts. The species do this cycle once a year, but many hybrids grow 2-4 times per year if the temperature is correct. When an Oncidium is happy it almost always makes more than one new growth from the base of the old growth. They can fill even a large pot in just 2-3 years. In a northern region, the short days may prevent growth after mid Fall, but the long days now will promote new growth.

Your outdoor temperatures now are fine for this plant. It would probably be fine with warmer temperatures, mid or even upper 30sC, and happy with nights down to 15C. You could have it out for the summer, and indoors for the winter. Oncidium hybrids are very forgiving, and it is OK to move them around. When the flowers start, put them where you want them to stay when they flower, or the spikes may twist to reach the light.

Deciding when to water, and what to use for potting media are skills to learn. If the plant is not making new growth, it is fine to let it get almost dry in the pot. You can tell how dry by lifting the pot and feeling the weight. When it is making new growth, new roots or new flowers, you will need to water more.

100% sphagnum moss can be used for medium if you water carefully. If you use 100% sphagnum, pack it tightly in the pot, so the plant cannot move right after you finish. Do not ever get all the moss completely wet. Water only the top for a few seconds. The water will spread through the entire pot and leave the moss a little damp, with a lot of air at the roots. If you completely soak the moss, all the air spaces will disappear, and it may take a long time for the water to evaporate. How often you will water depends on the ambient temperatures and humidity, but for Oncidiums in 100% sphagnum moss it might be once every 2-14 days for hot to cool weather. Go by how light the pot is, and dry the moss feels, not by the calendar.

If you use mixtures of bark chips, charcoal and/or perlite of any size, you will completely soak all the medium every time you water. Then if the plant is not growing actively, let it get almost dry before watering. Check how much the pot weighs to see if it is dry. When it is growing you can water more. With large pieces of medium in warm weather, people can water every 2-3 days. With small pieces, it might be every 3-7 days. But you must look at the plant to decide when to water, not the calendar.

Some people use a wooden stick (used for barbecuing meat) to check the water inside the pot. Put the stick into the pot. Leave it for 10-15 minutes. Pull it out, and see whether there is still some water inside the pot.

[Maria José]

Thank you again! Very helpful!