Den. antennatum problems

[SaraJean]

I have a Dendrobium antennatum that has been giving me problems for the past 2 and a half years but I have no clue what’s wrong with it. I have four other species and one hybrid from the Spatulata section that are all growing extremely well. It’s only the antennatum that is misbehaving.
Issues:
1. Weak growth. I’ve had 6 new growths since I bought it. 3 have been shorter than the previous growth (1 short, the next tall, the following short, and so on..). All are fairly skinny, but not dehydrated. I repotted it in June, the root system is fantastic :/
2. An already developed, mature cane just shrivels up and becomes hollow halfway down or at the tip. No warning, not squishy, just fine minute and the next... hollow.
3. Susceptible to disease. I will get random rotting, squishy leaves. The top section of a new growth will rot and die back in a day. Again, not an issue on any of my other dens in this section.

It should be obvious that I’ve not bloomed this one. I guess what I’m wondering is if this is just a weak or potentially virused plant that is not going to grow well no matter what I do. I’ve treated it with fungicide, Inocucor, and spot treatments of hydrogen peroxide (rot on leaves and canes, not on the roots). I’ve increased the air movement, checked the roots and made sure it was not getting too much direct light at any given time of the day.
Should I just chuck it in the trash? Or am I missing something?

---------- Post added at 03:55 PM ---------- Previous post was at 03:14 PM ----------

Some pics from today. The nasty cane and leaf (pic #3 and #4) just showed up today, hence my frustration
IMG_3282 by Sara, on Flickr
IMG_3280 by Sara , on Flickr
IMG_3278 by Sara , on Flickr
IMG_3275 by Sara , on Flickr

[estación seca]

I'm not sure, but here's my thinking. I don't have antennatum, but several primary hybrid seedlings from H&R. These get to be very large, tall plants. Even in your wet climate, that pot/medium combination probably dries out rapidly. I suspect it isn't getting enough water. Mine struggle if I let them dry out even once during the growing season.

I would up the watering on that plant a lot. Then, when it's making new roots, and it's a good time to repot, I'd move it into a much larger pot, with similar fast draining medium having lots of air spaces. Continue watering a lot. A wide but shallow container will stabilize the plant and permit more air at the roots, so you can water more.

[SaraJean]

Right now, this one and my other Spatulata types are getting watered every day. I was concerned that maybe it was too much until I repotted it and saw how great the root system looked. It’s in about a 2:1 mix of Orchiata and sponge rock. So far, that’s been working ok with it draining quick for the wet summers, but still retaining a little moisture to get it through the hot days.
The newest growth is promising as it’s the fattest one I have had (so far... I have been fooled before), so I’ll try tossing it in a shallower wide pot when that one starts pushing roots and maybe back off on the sponge rock? assuming I can get it to that point, lol. I couldn’t hurt and I really don’t want to trash it just yet. Thanks

[estación seca]

With the additional information, now I'm thinking the pot is so small watering once a day isn't enough.

[u bada]

I think it looks ok and with your other similar types doing well I think your culture is probably fine and wouldn’t change all that much. I only have one hybrid right now and I keep it dryer and full light so don’t think you should water more than you already do. Also I wouldn’t repot either if the roots look really good, that’s like the biggest challenge right there just getting good roots. I think it may just be taking it’s time to get to a point where it can take off.

That said, my concern would be the mushy leaves and hollowing out stems. I’ve been experimenting with Inocucor and that’s really worked out a number of my plants that exhibited what I call an imbalance of pathogens/ beneficial bacteria. Id say try using it again and apply judiciously. With kelpmax. I would just spray it down really well with solution for a few days straight, really Ray recommends soaking overnight for first application but with potted things I’ve done just really good spraying. Ray recommends just once a month, every 2 weeks max for follow up applications I think but I’ve pushed it to application once a week (just Inocucor) after initial 3 day application for 3 weeks to be clear of stopping rot and haven’t seen reoccurrences.

[King_of_orchid_growing:)]

Maybe the leaves are getting watered?

What time of the day do you water them?

Do not throw it away. It is ok.

[SaraJean]

Originally Posted by u bada

I
That said, my concern would be the mushy leaves and hollowing out stems. I’ve been experimenting with Inocucor and that’s really worked out a number of my plants that exhibited what I call an imbalance of pathogens/ beneficial bacteria. Id say try using it again and apply judiciously. With kelpmax. I would just spray it down really well with solution for a few days straight, really Ray recommends soaking overnight for first application but with potted things I’ve done just really good spraying. Ray recommends just once a month, every 2 weeks max for follow up applications I think but I’ve pushed it to application once a week (just Inocucor) after initial 3 day application for 3 weeks to be clear of stopping rot and haven’t seen reoccurrences.

I’ve been keeping up with the Inocucor at once a month but it might be time for this one to get a good long soak in the solution and try some repeat doses like you mention

Originally Posted by King_of_orchid_growing:)

Maybe the leaves are getting watered?

What time of the day do you water them?

Do not throw it away. It is ok.

I water in the mornings but the leaves definitely get water on them since it’s grown outdoors in the rain. During the winter it is in the greenhouse with a fan and I am a lot more careful with my watering. I guess it’s just confusing me since this doesn’t seem to bother any of my other Dens (or any other of my orchids). This year, I did add a fan to my summer grow space to help dry things off and cool things down.
Also, the tallest cane is the only one that left of the original. It keeps trying to grow, but it’s struggling. Maybe move it out of the rain for now and let it recoup?

---------- Post added at 08:33 AM ---------- Previous post was at 08:26 AM ----------

Originally Posted by estación seca

With the additional information, now I'm thinking the pot is so small watering once a day isn't enough.

That certainly could be the case. It’s in a regular 3” clay pot and if I’m remembering correctly, there might be a little LECA on the bottom as well. I wish I would have taken a picture of the root system when I repotted, it’s the only reason I didn’t trash this orchid back in June. It was a tight fit in the pot but with only 3 semi-decent canes, and the rot problems I keep having, I figured a larger pot would be pushing my luck.

[King_of_orchid_growing:)]

Maybe try getting it out to of the rain for now and see how it does.

Also maybe try what es had said and give it a slightly larger pot. It is worth a try if the roots are as strong as they're being mentioned to be.