How do I convince an Oncidium to bloom?

[DanielBear]

I have an Oncidium, have had it about 7 years. Based on web pictures I suspect it's Gower Ramsey, but not certain. It rebloomed during year two and year three, but never since then. Last august it was looking droopy so I repotted it, cut off some backbulbs and potted them, and they've each grown new pseudobulbs. So I think I have the growing part down OK. It has 8 mature pseudobulbs, all with healthy leaves, each bigger than the last.

Each time I think it's producing a new flower stalk, it's a new vegetative growth. The pseudobulbs get larger and larger with each new growth. I use the weekly-weakly method for fertilizing, with Schultz Orchid food, this is 19-31-17. I thought it might be too much nitrogen so I changed to Gro-More bloom formula which is 6-30-30. It's in a south window, but this time of year the noon sun is very high in the sky so it doesn't get full sun during the brightest hours due to roof overhang. When it bloomed previously, it was in an East window and frankly was neglected. Maybe that is the key.

There is another new growth that is vegetative, and an additional one Im not sure about yet, but give past performance, Im not getting my hopes up yet.

Are there things I should change? No plant food at all? I usually do use rain water in the mix. The potting mix was commercial, it had fertilizer pearls in it, but I imagine those are long gone now, it's been a year. Does it need a dry spell? Is day length an issue? Not enough light could be a factor, but really it's getting more than it did in the past, the leaves are grassy green, and moving it outside resulted in sunburn on 2 leaves - but it still has lots of healthy nonsunburned leaves.

Thanks for your advice. I'm pleased that I haven't killed it, but there are lots of types of green plants, and I would like for this one to bloom

[Lagoon]

Hi Daniel

Some oncids are just stubborn, for those, I allow them get drier toss them out in a temp of 60 to 65 degrees for 1week, bring them back inside then 3 to 5 days of darkness, after that back into suitable lighting and resume waterings.

I have seen spikes as early as 4 days later, although 2weeks would be more normal.
I would give a good flushing of the media get rid of any ferts and go to a more balanced fertiliser.

Whats you're potting media?

[DanielBear]

Gloria

Thanks for the advice. I'll set it outside at night for a couple of weeks. The nights here are quite cool. During the winter, my plant room is about 50 to 55 at night and 65 to 70 during the day. In the summer it's about 10 degrees warmer.

[Ray]

Daniel,

What kind of light does it get, and have the plants completely taken over the pots yet?

[DanielBear]

Ray,

It's in a south window, up against the window. When the sun is high in the sky, it's shaded by the roof overhang, but except for the 2 brightest hours of the day the plant is getting full sunlight through a glass window, no screen.

I live in Pacific Northwest, current the days are as long as they get, starting to shorten.

I tried sitting it outside but even an hour and not at high noon, a couple of leaves developed sunburn.

I do have some Dendrobium nobile, a couple of Cattleya, and a Cymbidium in full sun, and and they seem quite happy. But the Oncidium doesn't seem to be designed for full sun.

This plant does seem to be taking over its pot now. It seems to add pseudobulbs in a corkscrew fashion, one on top of the previous one, so it's tending to grow upwards. I could experiment some, with the 1-year old plants that I grew from backbulbs from this plant - One has a fully plumped out pseudobulb now. I expect they are too young to bloom, I don't know.

[Hedge]

Nice Idea about the darkness spell, Gloria, I shall try that with my reluctant flowers in this group

thank you

[Anisa]

Hmmm.... darkness and dry spell you say? I have one like that - huge 6-8 huge pseudobulbs. Gets lots of light, outside in temperature in about 80 - 95F but no flowers Perhaps I should try a torture

[Ray]

I have such oncidium hybrids growing alongside of vandas in my greenhouse, and they are fine.

The fact that you started to detect leaf burning tells me two things: 1) The change was too drastic - you should transition plants to brighter conditions, and 2) it must not be getting as much light as you think it is (or it would not have burned in the first place).

[WhiteRabbit]

well the Oncidium genus for me has mostly been my easiest lol - I don't do anything special to get them to bloom. My small ones (Twinkle, and a NoID) seem to like getting a bit dry between watering - my Sharry Baby, tho, I keep moist.
The small ones have both spiked in west facing windows that get some direct sun, but not all afternoon. Sharry Baby was in an shady east facing window til early summer, and now is on my east facing sheltered porch and is in spike .
My Onc Carnival Costume (hybrid with Tolu) I do allow to dry completely before watering - it bloomed earlier this year after wintering in west window ...

I can't really say about temp variations needed, as where I live there is always a BIG swing between day and night temps most of the year. And being a fairly mild climate (and me trying to save money on gas and electric bill) I have the heat set low in winter - so I'm not sure if that might aid blooming or not ...

[Izzie]

You could always threaten it by holding it over a pool like Sue does.