Dendrobium Spike stopped growing?

[rbarata]

LOL Right. Den Phal. Sorry about that.

In that case I don't grow them so I can't help you. I think Ray gave you already some pointers.

[Ray]

Short-term stresses are usually not an issue, unless it is extreme. Usually, a failure to bloom is the result of a longer-term issue - a cool-growing plant being kept too warm, for example. A few days of warmth aren't likely to cause an issue any more than a few days of cool would fix it.

In the last photo, it looks like it is the largest of three growths that have not bloomed before. Maybe it just isn't quite mature enough yet.

[Cymbaline]

Originally Posted by Ray

Short-term stresses are usually not an issue, unless it is extreme. Usually, a failure to bloom is the result of a longer-term issue - a cool-growing plant being kept too warm, for example. A few days of warmth aren't likely to cause an issue any more than a few days of cool would fix it.

In the last photo, it looks like it is the largest of three growths that have not bloomed before. Maybe it just isn't quite mature enough yet.

Could you elaborate by what you mean as "mature". Do you mean that the stalk itself or the plant? I ask because I am pretty sure the plant itself has had blooms before and I think it's about 10+ years old.

[Ray]

A division of an already mature plant is certainly expected to bloom sooner and more reliably than an immature plant that's "growing up", but if that plant is moved to different environmental conditions, it might back off until it adjusts.

As I said in the article I linked earlier, a plant basically has three uses for the nutrients absorbed and fuel created: maintenance of existing tissues, growth of new tissues, and reproduction.

Those reserves are created via various chemical processes that are controlled very much by light levels (including darkness), temperature, availability of water, etc. If any of those parameters do not meet the expectations of the plant, it won't build up the reserves at a sufficient rate, so won't "risk it" on the reproduction front, so won't bloom.

I'm guessing that the plant's "decision making" is based as much by the rate at which those processes function relative to each other, as much as how much of the reserves are already stockpiled. A smaller plant under great conditions will bloom better than a large "specimen" that has been moved to lesser conditions.

[SouthPark]

Originally Posted by Cymbaline

I know you don't know and not looking for a concrete answer. Just speculating.

I think that in order to make any educated guesses about the spike stopping development - that's assuming it is was part of a spike - there will be a need for history details. Eg. environment temperatures during day and night. Where it is grown, indoors or outdoors. How much light it receives during the day, and what intensities, and whether the orchid's growing conditions had changed abruptly etc.

The nice thing is that the plant itself looks just fine. If no spike this time, then there's always next time. Keeping the plant in good health and shape will see plenty more flowering opportunities ahead.

[Cymbaline]

Originally Posted by SouthPark

I think that in order to make any educated guesses about the spike stopping development - that's assuming it is was part of a spike - there will be a need for history details. Eg. environment temperatures during day and night. Where it is grown, indoors or outdoors. How much light it receives during the day, and what intensities, and whether the orchid's growing conditions had changed abruptly etc.

The nice thing is that the plant itself looks just fine. If no spike this time, then there's always next time. Keeping the plant in good health and shape will see plenty more flowering opportunities ahead.

Okay so history. The plant is older than 10 years. It was my aunts but she passed away in 2017 leaving me this and a Oncidium. They were in the same pot.

Mid 2018, about June I reached out on a FB group to start doing something with these guys. Separated them into their own pot and they lived on my kitchen's window. See picture

They received some direct light in the evenings because the window looks out to a cover patio that is West - South and the setting sun would shine in directly. Otherwise not much sun.


2019 I started with actually taking care of it. Not sure exactly when but in May I bought a grow light, Blue/Red. I also started to watering them both about once a week with diluted Dyna-gro Orchid fertilizer.

That's when the Dendrobium started to create it's limb / bulb .

So between May - end of Aug / early Sept. It lived under the light, above the sink ( on top of a cookie cooling rack ). There was water in the sink for humidity. Temperatures during the day was around 74F, 76F or 78F downstairs. Night it was probably around the same. We turn off the air conditioner downstairs at night.

I soaked both plants once a week , usually with some Dyna-gro.

When I started to monitor humidity it read about 48 usually.

September, 2019

In Sept I moved them to a room to reclaim my sink. I bought a rack and the window is East. So they got east sun in the morning and the one grow light.

Daytime temps was about 78F - 80F . Night it is about 63F - 65F.

I bought repotme orchid food and started to use that instead of Dynagro

Bought a humidifier for the room and tried to keep it at 50 - 55 percent.

On Sept 26 I bought a Monnierara Millennium Magic 'Witchcraft' and after reading that they need more light, I bought two more grow lights.


I bought an Elizabeth Ann about this same time and because I read that it doesn't like temperatures below 65 I put a heater in the room set to 65F.


On Oct 3, I bought Jack's 10-30-20 fertilizer as suggested by the American Orchid Society for my Catasetum Witchcraft but I probably also used it on my Dendrobium.

I never used full strength.

On Oct 7 - 9 I bought Physan because I was concerned about a fungus infection with one of my new orchids. I used the diluted suggestion / maintenance on the Dendrobium and the rest. I noticed the next day that after I did that , that one of the leaves on the Dendrobium turned yellow. I maybe wrong but I think the spike was still growing.

On Oct 17 I found the Catesetum had spidermites and sprayed it and the others with 70% isopropyl alcohol .

I noticed around Oct 23, 24 I think that the spike hadn't gotten any bigger. I took a picture on the 26.

---------- Post added at 02:16 PM ---------- Previous post was at 02:12 PM ----------

Originally Posted by Ray

A division of an already mature plant is certainly expected to bloom sooner and more reliably than an immature plant that's "growing up", but if that plant is moved to different environmental conditions, it might back off until it adjusts.

As I said in the article I linked earlier, a plant basically has three uses for the nutrients absorbed and fuel created: maintenance of existing tissues, growth of new tissues, and reproduction.

Those reserves are created via various chemical processes that are controlled very much by light levels (including darkness), temperature, availability of water, etc. If any of those parameters do not meet the expectations of the plant, it won't build up the reserves at a sufficient rate, so won't "risk it" on the reproduction front, so won't bloom.

I'm guessing that the plant's "decision making" is based as much by the rate at which those processes function relative to each other, as much as how much of the reserves are already stockpiled. A smaller plant under great conditions will bloom better than a large "specimen" that has been moved to lesser conditions.

Thanks Ray. I don't know what may have changed while the spike was growing to cause this. Nothing I can think of changed while it was growing but maybe something before the growth and then it just gave up.

[SouthPark]

Originally Posted by Cymbaline

2019I also started to watering them both about once a week.

Thanks for sharing the history! The conditions and schedule seem quite ok. Just continue with it, and see what happens for the next round - next spike development.

Could also keep to the once a week with weak fertiliser solution, or make it even weaker. My outdoor dends don't even get fertiliser solution, and they flower every season. This doesn't mean that they don't get fertiliser. They do - but it's due to bug/insect activity in their pots (I suspect this - as for 1 of my outdoor dendrobium that I had put it under a shrub for a long time, I decided to repot it into a bigger plastic pot, and noticed insects running around and ants eggs etc etc). The orchid wasn't harmed at all by the activity - but probably benefits from it.

On the other hand, all my other orchids do get fertiliser solution (relatively weak) - once a month. I use cal-mag (weak) once a month too, but I apply the cal-mag around 2 weeks after the fertiliser.

Also - consider the watering schedule too. If it turns out that a little more than just once-a-week is necessary, then take a look into that too.

[Ray]

Based upon the info in the plant history and what info is lacking, I can think of four potential reasons the plant hasn't bloomed:

1. Insufficient light.
2. You made a change in the conditions, so it is in the adjustment mode.
3. Excessive nitrogen (tell us how much per gallon for each formula you've used and how often you feed)
4. Infrequent watering.

That last is just a guess based on no info. Folks often misunderstand the origin of-, and reality behind "orchids must dry out between waterings" and take it to extreme. Water is the driving force for growth.