Factors affecting number of buds per inflorescence

[yousillygirl]

Does anyone know which factors are key to increasing the number of beds per inflorescence? Is it nutritional, or light/temperature, or what?

My mini-dendrobiums used to produce 5-6 per inflorescence but in the last few months, the number seems to have dropped to the 2-3 range. I grow in s/h, if that makes a difference.

Thanks!

[Ray]

Light- and nutrition levels can be the most significant factors, but lots of food that results in excessive nitrogen can be counter-productive, and any other conditions that are not part of good culture can affect that, too.

If you tell us more specific info about your current culture - all of it - we can be of more help, otherwise we're just "shooting in the dark".

[yousillygirl]

Thanks Ray.

Currently I grow in s/h in my laundry room, which has a western exposure and decent breeze. The plants get fairly strong light at about 3500-4500 ft candles, but I monitor pretty closely and there haven't been any signs of burn and the leaves aren't reddened or dark green. Temperature wise, it's probably about 28-30C during the day. And I'm in Singapore, so the humidity is always about 80%.

I flush weekly with MSU + RO at a rate of 1mL per 1L, seaweed gets added about every 3 or 4 weeks.

[yousillygirl]

I am also getting new canes and generally good vegetative growth. Could that be a factor, the plant diverting energy into growth and flowering less?

[NYCorchidman]

Light is the most important factor when other things are done correctly.

I water plants well and fertilizer not so much.
Giving the maximum light short of burning seems to bring out the best flowering results in pretty much anything.

I notice jump in flower count in both dendrobiums and phals under highest light they can take.

With western exposure, how many hours of light does it get? If it stays just bright all day and then some sun in the late afternoon, it may not be enough.

What else are you growing and flowering in that same location where your dendrobium is?

I would say at least half day sun (filtered out just a little bit) to all day for the best flowering.

By the way, is this the second flowering off the same cane? You might want to give more time to your plant and see what happens. If the flower count stays low, then there is a problem.

[My Green Pets]

Could too much nitrogen be a factor, as Ray mentioned?

[NYCorchidman]

Definitely.

Too much nitrogen result in larger than needed vegetative growth, which are actually weaker and thus more susceptible to diseases. Also, too much nitrogen can keep plants from flowering.

But the evidence of too much nitrogen would be rather obvious.

All these are for non-orchid plants, but I assume the same apply to the orchids.

[Bud]

Temperature plays a big factor for miniature Dendrobiums. If you give it cooler nights then there will be more flowers that are bigger, flatter and with vivid colors....longer days means growth periods and shorter days means dormancy.....it is the spring light exposure that triggers more spikes and more flowers= but since your area is equatorial then you don't have to worry since your length of daylight doesn't vary as much as my area in the temperate zone.
The other members gave you important advice regarding your growing this kind of plant.

[yousillygirl]

Ok, thanks to everyone!

It never occurred to me that the plants might still not be getting enough light at those levels - will try removing some of the shading cloth on the window and see if that helps.

I also have oncidium, tolumnia and brassavola in the set-up, all of which have flowered well, but admittedly are closer to the window sill....

[james mickelso]

The biggest factor governing flower count, all other things being equal, is the number of canes, pbulbs, leaves on the plant. The older the plant, the more growth, the better the flowering. Even orchids that were grown in the commercial sphere and flower with no more than a few pbulbs, have one, maybe two flowers. But grow a specimen with pbulbs galore and the flower count per pbulb can get fairly high. Nutrition, good water, the required warmth and correct level of light are all cultural necessities, but flower count is mainly governed by age of the plant.