Generally you want to leave them on as they serve as food reserves for your plant (like if the roots rot...these back bulbs will serve as a source of energy to help the plant recover). However, there are a couple occasions where removing them is appropriate.

1. Propagation: these backbulbs have dormant eyes from which new growth develops. You can divide your plant and pot up these back bulbs to get new plants.

2. Size maintenance: If your plants are overgrown in a 6" pot, but growing space won't allow you to move to an 8" pot, you can remove the back bulbs so that it can stay in a 6" pot. You would pot up the newest growth to keep and either discard or trade the old pbulbs.

RB, PLEASE share your Oncidium culture!

It appears that you are doing very well!!

--Stitz--

Stitz,

For what it's worth, here's what I do. The oncidium sits on a window sill that faces east. Gets bright light all day and early morning sun except when the sun gets really hot, and then I move the plant to the nearby kitchen counter until the sun climbs higher.

We water the plant about once a week, fertilizing it each time, using about 1/8 tsp. powdered orchid fertilizer to two cups water. Once a year after blooming I take the plant out of the pot, remove the dead roots and repot it with fresh orchid bark (small size). It blooms once a year starting in July or August and lasts for several months.

The plant tends to sprawl out horizontally. To prevent this I wire the psuedobulbs together using plant ties. This keeps them vertical.

I have a Phal that does very well with similar treatment. It blooms each years starting in December.

Good luck!

RB

Great tips; Thank You!

--Stitz--

In California perhaps an east window would be enough, but here on the east coast in New Jersey my oncids needed a west window.

I found that watering once a week caused the leaves to accordian pleat. I had to water every three or four days. Keep an eye on your leaves.

Orchid 126,

Accordian pleat! Hmmmmm! I have a miniature Phal in a four or five inch pot. Its bottom leaves are always wrinkled (accordian pleat?), whereas my big Phal in a six inch pot always has bright shiny leaves. I have always assumed that the small Phal simply has a different kind of leaf surface. It's been on the same once a week watering schedule as the bigger plant. Sound like inadequate water?

RB

Perhaps. It's hard to tell. Do you use the skewer method? If not, you might try it, and then you can see that if the larger pot needs water the smaller one may or may not, or you may find that the smaller pot is drying out more quickly than the larger pot.