brittle roots in a dendrobium nobile - Orchid Board

zygophalden · #1 10-08-2019, 06:26 AM

hello, I recently purchased a Dendrobium Nobile from a nursery. When I purchased it everything looked all right, beautiful flowers, good roots and overall in a pretty good condition.
Yesterday I noticed the roots are brittle a bit even though I am watering using the skewer method- when the skewer a cool and a bit dry I water it because from what I read, dendrobium like a bit moist media. is it possible I don't water it enough?
additionally, the canes lean to the side a little and pull the roots with them a bit so you can see them from the top. should I repot it so the roots will be in the media?
I apologize in advance about the messy structure, wasn't sure how to explain everything.
edit- added pictures of the orchid and the roots. I am pretty sure I should make sure they stay inside the pot but don't want to mess with them unnecessarily.

rbarata · #2 10-08-2019, 08:52 AM

Welcome, zygophalden.

Please post photos so that we can take a look.

Thank you

aliceinwl · #3 10-09-2019, 12:51 AM

If the canes aren’t wrinkled you’re doing fine on watering. I’ve found that I have to stake any cane that I don’t want to lean. The roots also are fairly brittle on all of mine too. Given the state of the roots and pot, you may want to consider re-potting and upsizing the pot a bit once it’s done blooming.

zygophalden · #4 10-09-2019, 10:23 AM

thank you very much

Shadowmagic · #5 10-09-2019, 04:31 PM

what you have described is what is happening to the roots of one of mine. Unfortunately it has been going on for months and now the plant is starting to suffer.
I didn't pay much attention to it because I thought I had done everything I could do for it and I actually bought 2 at the same time. One is doing great, the other one is not so if one doesn't make it I still have the other one but your post made me think and have a closer look and I discovered something...

I don't know how I missed this when I re-potted it but look what I found hidden away this time round:

brittle roots in a dendrobium nobile-img_4198-jpg

brittle roots in a dendrobium nobile-img_4199-jpg

brittle roots in a dendrobium nobile-img_4200-jpg

It's been suffocating the roots.

I would highly recommend you get a very light and airy medium for your dendrobium.

I find clay pebbles work but they need to be wicking up water and stay damp constantly otherwise the roots dry very fast.

coco does not work long term in my experience - it doesn't let enough air in.

Bark is good, add in some perlite and you have a great airy mix.

I wish I had checked the roots sooner instead of thinking I had already repotted it - in my defence it was one of my first orchids but looking at the picture I didn't even rince the old coco off the roots before repotting which is something I definetely should have done - the plant would be looking a lot better by now

Roberta · #6 10-09-2019, 05:12 PM

Shadowmagic, in spite of the mess in the middle, it looks like you have some very nice roots. So once you get it cleaned up and into fresh new medium, I think it will be fine. Look for new growth in spring.

I have found coconut to be bad news - the fiber does, as you found out, hold too much water. But I have discovered another issue - salt (like in ocean salt)... I used to use coconut husk chunks for orchids that like to stay damp, like Cyms, and for a number of years it worked great. Then came the tsunami in 2004 that inundated significant parts of Indonesia - including coconut trees. After that, the coconut husk chunks that I got caused bad salt damage to plants - experienced by everybody I know that used the medium. Even copious washing was not sufficient to clean it. It may be better now as plantations are recovering, but I have still found it to be pretty sketchy (and where it used to be very long lasting, now it's trash in 2 years or less). Nobody grows coconut specifically for orchid medium, it's just a byproduct and so will suffer if the source trees suffer and there isn't good water to clean it before packaging. Bark is much better (until the next disaster) but also being a byproduct, it can also be highly variable, so still bears watching.

rbarata · #7 10-09-2019, 05:18 PM

I would repot it with a new and fresh medium: medium sized bark+LECA, nothing more.
And I would keep the same pot, unless there's a large root ball inside it now. Nobiles like to be root bound and really dry in winter until new growths start to appear in spring.

zygophalden · #8 10-11-2019, 09:36 AM

Is there a possible substitute for LECA? I don't think we have it in my country.

Veksa · #9 10-11-2019, 09:43 AM

Quote:

Originally Posted by zygophalden

Is there a possible substitute for LECA? I don't think we have it in my country.

Where do you live? Do you have Ikea?

zygophalden · #10 10-11-2019, 02:40 PM

Quote:

Originally Posted by Veksa

Where do you live? Do you have Ikea?

I have IKEA but they don't sell it there for some reason last time I checked. However, If I am not wrong, Leca is clay pebbles? if so, I believe I found where to buy. Are there sizes or certain kinds of LECA?