Olympic has a lot of Gramms now

[aparnamane]

Originally Posted by estación seca

Sorry, didn't have a chance to respond before now.

Oncidiums should never dry out. These tiny mericlones are even more sensitive to drying out than are larger plants. Most of them are not large enough to flower on arrival. Howeara Lava Burst is a miniature that is blooming size in those tiny Olympic Orchids pots, and doesn't get a lot bigger.

Even going dry once may cause loss of many leaves from these tiny plants, and stop the plant from growing for a long time. I don't believe I've ever had a problem with keeping the sphagnum too wet. They use water so rapidly it doesn't stay saturated for long.

Olympic ships plants in nearly new sphagnum, so I rarely repot them until they've outgrown the pot. I mostly move them to semi-hydroponics. Rather than disturb the roots, I put the entire sphagnum root ball into a container, and backfill with LECA. I set them at one edge of the transparent plastic container, with the growing direction towards the center. It can take months for new roots to penetrate the LECA. I need to keep the moss moist until the roots grow out.

Ambient temperatures and light affect water use. Because of their ancestry, Twinkles and Lava Burst are less tolerant of high temperatures and bright light than are most other Oncidium hybrids. Most home temperatures are fine. If you let your house get quite cool in Winter, or quite hot in Summer, they might become unhappy.

They both flower in bright shade. If grown close to lights, or a window, they may overheat, and they don't need that much light. Bright shade is fine for these.

When you put the sphagnum root balls into a bark mix, I would suspect roots never grew into the less hospitable bark. You would need to keep the bark quite moist to entice roots into it, being sure it still has plenty of air spaces at the roots. It would take a while, but roots would eventually grow into the bark as the plant grows. I could envision needing to water a plant moved to fine bark almost every day until it grows into the new medium.

Observe how they use water. Water a new one in the packed moss thoroughly. Feel how heavy it weighs. Lift it every day and see how rapidly it lightens. During warm weather I have to water small mericlones from Olympic almost every day.

And don't be in any hurry to repot. They should outgrow the pot before the moss goes bad. If they haven't, you probably haven't been watering or fertilizing enough.

I don't have your plant in front of me, but I suspect the pseudobulb didn't rot. It is more likely it died due to underwatering. It can take quite a while for a plant to wake up and grow again after that happens, so don't give up. As far south as you are, these can grow all year.

Hi ES,

Thank you so much for the detailed information.

I don't have LECA, but I do grow some orchids in lava rock in semi-hydro setup with river pebbles on top layer, I think I will use your idea to use similar setup with lava rock to drop the root ball in transparent pot.

I will update here.

Thanks once again for your reply.