Don't know where you are located, or anything about your growing conditions, so not knowing that, in general, here are a few suggestions.

First suggestion.....go to the American Orchid Society web site and find the culture sheets for Dendrobium Phalaenpsis Orchids, then do a bit more digging to get as familiar with the growing characteristics and cultural needs of this type plant.

Now, lets talk about your plant. You have an apparently healthy blooming size Den. Phal. The three old bulbs on the right are a vital part of the plant, they have viable roots growing from them and those roots are picking up nourishment that is being stored in the older canes. These old canes have already bloomed, and will not bloom again. As the new growth emerges, it will not at first have roots, and will draw nourishment from the older canes. Normally the plant will suck the oldest cane (the short stumpy one on the right in your photo) dry, and it will shrivel up and die. At that time you can cut it off the pant if you want, or just wait and take it off at the next repotting.

When the new growth is about twice the size it now is, it will begin to put out its own roots, and on maturity later in the summer it will bloom.

Your job now is to do all in your power to encourage this new growth to become as large and as healthy a cane as possible so it will have multiple bloom spikes with lots of blooms.

Lots of sunshine (strong, but not direct sunlight during the hot part of the day) and water (flood the plant with water each time it becomes almost dry) and feed it well while that new shoots are growing (30-10-10 fertilizer half the recommended strength twice month). After the new growth is mature, I would change the fertilizer to a balanced (10-10-10) fert. or just cut off all fertilizer while it is dormant.

Now, for the one problem I do see.....Den. Phals. do like to grow in pots with their roots a bit cramped, but what you have goes beyond that.....

I would suggest repotting the plant immediately. It should have been done while the plant was dormant, before the new growth started, but you can take it out of its present pot as carefully as possible without badly damaging the roots. Clean the old potting material off the roots as best you can without doing too much damage to existing roots. Get some orchid bark mix and a pot large enough for the current root ball to fit into easily (lots of drainage holes). Wet the bark mix, put the orchid plant in the pot and fill in all around and under the roots with new potting mix. The base of the new growth should be sitting right at the top of the new mix.

Keep the plant in light shade with no water (you can lightly mist the canes and new growth if you want to) for at least a week to give the roots to heal and start sprouting new roots.

It is critical that the plant be securely placed in the new pot so it does not move about in the mix. If the plant moves around in the pot when the new roots are growing, they will be damaged and stop growing. Use one or more rhizome clips (google that, because I am not sure I can write a picture of one here....☺) After a week or so, begin the fert. water routine described above.

Good growing......post a photo when you get blooms, its always nice to have something besides Phalaenopsis to see and talk about.

Bill

Shavedmonkey,,,,,thanks. It always nice when a new grower with a question can get a consensus of opinion. Orchid growing becomes much more enjoyable then.

Oh for the ability to say much with few words.......I simply cannot cultivate that ability. ☺

Bill

You need to provide information about where you live. What Country, State, or zone.

Jane

There is no need to repot that plant. Dens like to be underpotted. The pot has slits for good drainage. Now it is imitating nature at its strongest. To pot now is just to satisfy the human condition not the orchid. It will on its own grow over the pot. At that time a proven next step is to put the overgrown pot in a pot. Not now. A year or 2 later. It is growing on the medium not in it. That is natural. Too often growers like to force the plant to grow in the medium. Not on it. A repot now will certainly set the plant back! No need. Let the orchid be an orchid! Also this is a beginner. That triples the risk.

Thank you shavedmonkey and Bill!

I think I'll keep it the way it is for a while before attempting to repot. It still has its flowers on, and has a new growth coming out of it, so it probably really is happy! I'll learn as much as I can in the meantime!

As for my location, I'm from Dhaka, Bangladesh @Jane and Bill :)

Also, here is a photo of the whole plant :

I've been soaking the roots in water, making sure they don't ever get too dry. It's been enjoying bright indirect light since I bought it. Average temperature at this time of year is 28-29 degrees Celsius!

In time the pot will be covered by the plant with lots of blooms. Do not let the roots bend. That will cause them to break. When the plane is out of bloom see if you can find an outdoor spot. It is better to not move the plant and spray it were it grows. But during the bloom it wants your eyes.

My kitchen window ALWAYS has room for blooming plants that "want my eyes" :)