Pseudobulb maturation

[malteseproverb]

Of all the orchids I've owned that require pbulbs to form and develop, I've had no luck in getting them to do so. Instead, they either barely become bulby (see last pic for what I mean) before putting out more shoots or they remain shoots with extremely long leaves. Is there a particular reason for this? It's across all different kinds, including oncidiums, brassia, encyclia and cymbidium.

I grow them in 7a zone indoors only, west and south exposure with huge tall windows, quarter strength fert year round, with varying degrees of success in getting humidity above 40 percent, and temps usually above 70. Any advice would be helpful.

Pictured is an odontoglossum I've had for about a year, which unlike the others has only put out the 2 shoots (instead of putting out 2 shoots that then put out more shoots...). You can see the long long leaves but the bottoms haven't turned bulb-like despite growing like this for many months. This one sits in a southern windowsill and is a definitely not the happiest orchid of my collection so maybe not the best example. Only in the past month has the bulbiness sorta started (last pic) which is about as far as it gets for most of my chids.




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[malteseproverb]

The best example is really this oncidium which has 2 mature bulbs and 6 immature. It's so unwieldy it's almost impossible to get a good pic.




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[Optimist]

I am wondering if there is an obstruction to the plant converting water and sunshine into glucose, which is what is stored in the bulb's cells? Not enough water or sunlight can mean less food stored, and thus smaller bulbs. Oncidiums are fairly high light orchids. I send mine outside when the wether gets better and they sunbathe and grow for several months under an appropriate shade tarp. During the warm weather they usually also get 2-3 waterings per day. This, in a way, simulates the monsoon rains. I have also stopped listening to the info about not watering at night as night and early morning is when it rains.


It seems to me that a good bulb might take a year or more to fully form. The water and sun need to also be applied at a growth time in the life of the plant. Watering and exposure to more sun can help but during a time when the plant is receptive to them.

[silken]

What type of fertilizer are you using? The first number denotes the ratio of nitrogen. If it is a lot higher than the middle and 3rd number, you may be stimulating leafy new growth. The middle number which is phosphorus helps mature and harden off growths and promotes blooming. If you aren't already, I would suggest trying a balanced fertilizer such as 20-20-20 or 10-10-10

[malteseproverb]

I was using miracle gro orchid fert (30-10-10) for a while but stopped around July and now I use dyna-gro grow at 1/4 strength plus a seaweed fertilizer. I stopped the miracle gro precisely cos I figured it wasn't balanced enough. During the summer I used it once every week but I think I'll taper off to once a month now.


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[silken]

That may have been causing the problem. Low light if that is the case will make weak lank growths also. But it sounds like you get a fair amount of light.

What is the DynaGro ratio?

[malteseproverb]

Sadly I live in an apartment with absolutely no ability to put mine outside. I -was- wondering if the bulbs simply take a while to form. Does anyone know? I did have a brassia for 3 years that had no ability to give me mature bulbs though it was also my first chid and a totally failed experiment (it was also my first orchid to die! Who woulda thunk).


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[malteseproverb]

Dyna gro is 7-9-5. The leaves are light green, so I don't know if light is an issue. South and west exposure in 8 foot tall windows without curtains. The whole place gets lit up on a sunny day and it barely rained this summer.


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[silken]

It sounds sunny enough and that sounds like a more balanced fertilizer. If the plants are growing, you can still fertilize them weakly weekly in the winter. Every month or so give them a good flush with clear water to remove excess fertilizer salts. If growth slows, they may need less water too.

Many orchids are fairly slow growers and it is not unusual for a growth to take most of a year to fully mature. Once mature, they often put up spikes and then begin producing a new growth or two. Because they are slow, it takes a while to see any improvements from the fertilizer change or anything else you do also. Just have patience and I am sure they will start to mature and bloom. Many people grow on window ledges or indoors under lights so I'm sure you will begin to see some success. The plants look clean and healthy so that is a good start.

[malteseproverb]

That's for your advice silken! I know being patient is key and I definitely think my plants are doing otherwise better than I expected. But I've had this question on my mind for a while and I've never seen it addressed despite extensive googling. I'm still wondering if I'm the only person who has had this kind of trouble so hopefully if anyone has experienced this before they will comment here.


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