Oncidium with only 3 flowers on a tiny spike?

[King_of_orchid_growing:)]

I know some people advocate using eggshells as a source for calcium for plants, but I tend to be on the same boat as you, and am quite honestly unsure if it really does provide a plant with an absorbable and adequate source of calcium. As far as I know, the calcium from eggshells does not readily dissolve in cool or room temperature water.

However, limestone rocks do dissolve in cool or room temperature water rather easily. A better source of calcium for plants would be dolomite, powdered lime, or limestone.

With this particular Oncidium, I think that calcium is not top priority for this orchid. I'm by no means saying that this plant does not need calcium. But what I am saying is that, calcium plays a smaller role in this orchid's well-being than, say, for example, certain Paphiopedilums.

In regards to the plant receiving lighting.

The amount of hours the plant is exposed to light seems appropriate enough.

But…

I think you need to provide the plant with a stronger intensity of fluorescent lighting. It may not be getting the correct intensity of light that it needs to produce enough sugars to warrant larger growths, (I'm speaking strictly in terms of your fluorescent lighting).

Here's what I mean.

1. Plants use photosynthesis to produce sugars.

2. Sugars are a plant's food source.

3. If the plant is exposed to the proper intensity and an appropriate number of hours of light without sunburning the plant, it will produce more sugars than a plant that is provided light that is lower in intensity and shorter in the number of hours.

4. The pseudobulbs of an orchid are modified stems. They serve as storage organs for sugars and water. Sugars and water are stored in these pseudobulbs because in the wild, the area the orchid grows in may have strongly seasonal rains, or it may experience unexpected periods of drought. In either case, the pseudobulbs can provide the necessities of the plant during these harsh conditions.

With the proper lighting, the plant can produce more sugars. More sugars means it will start storing them in newly developing pseudobulbs. The more sugars the plant is pumping into the newly developing pseudobulbs, the larger they will be.

Note #1: Depending on the type of orchid, given "ideal conditions", they will only get as large as their genetic potential allows them to be, no larger.

Note #2: I'm fully aware that your plant is a man-made hybrid. The pseudobulbs are present because the orchid's parents were able to genetically produce them. However, regardless of wild orchid or man-made hybrid, if the plant has a pseudobulb, the purpose and function of a pseudobulb is as I have described, generally speaking.

5. The basic run down is that, a plant needs nutrients to aid in the efficiency of the photosynthetic process. Those nutrients are in the form of nitrogen, phosphorous, and potassium. Other nutrients are calcium, magnesium, iron, zinc, manganese, etc. When provided these nutrients, they are able to physiologically function more efficiently and be in better health.

6. Flowers take up energy to produce. The more energy it has, the more likely it will produce somewhere around the maximum number of genetically potential blooms it can.

Adequate lighting will provide the energy the plant needs to put out a flower. Nutrients ensure the plant gets what it needs to physiologically function properly. When it gets the energy it needs and is "physiologically in balance", it will give you the blooms that it should be able to produce.

7. Moral of the story is:

A) Provide adequate day length and correct lighting intensity.

B) Provide the plants with some nutrients.

Maybe over time, you will see the orchid getting larger and producing better blooms.