Dendrobium Nobile curious burn
 

Hello, I noticed today that my Dend. Nobile has a curious burn it's biggest new lead and am wondering what the cause could be. The plant did recently, and may still, have mealybugs if that is a factor.

The burn is the light brown on the left leaf in the picture. Many thanks for any thoughts.

I apologize for the picture quality but my camera isn't particularly good >.<

http://i192.photobucket.com/albums/z...g?t=1269824284

How long have you had it for?

What kind of fertilizer are you using (NPK, brand, urea free or not)?

What is the concentration of fertilizer you're using when you fertilize?

How often do you fertilize?

Do you use tap water to water?

How are the roots?

How long have you had it for?
I've had it since February 23rd, it seems to be pretty young, the two new leads were rather small when I first got it.

What kind of fertilizer are you using (NPK, brand, urea free or not)?
Miracle-Gro water soluble with Micro nutrients. NPK 24-8-16. I did a quick search and it apparently includes urea nitrogen although it says nothing about that on the box itself.

What is the concentration of fertilizer you're using when you fertilize?
I use a pinch of the crystals, just enough to grab between my thumb and forefinger, dissolved into about a litre of water. It should be below the dose listed on the box.

How often do you fertilize?
Whenever I water, I was told a while ago that it's a good idea to fertilize weakly constantly. I normally flush once a month and fertilize about once a week when I water it.

Do you use tap water to water?
Yes, I have no other sources of water and am currently drawing the line at purchasing special water for my plants because I feel right now that that way lies madness...

How are the roots?
With a minimal amount of prying, the roots below the media/the ones I can see among the media *sphagnum moss I assume* are green. It has several roots above the media which are usually white as my growing location is not particularly humid.

Nobile type Dendrobium are deciduous and all leaves turn brown and die each year.

I seldom pay any attention to any leaf damage as life span of a new leaf is only one year.

The brown is not burn as Nobile type dens can take full sun without burning. Burn will not show on any leaf at the tip on a downward curved leaf. Heat rises and the burn (heat build-up) would be on the highest point of the leaf not the lower tip.

While I agree it's not a result of sunburn, I don't agree that it is becoming deciduous.

This is the wrong time of year for it to go deciduous.

They start going deciduous and then dormant right around mid to late fall.

It's spring in the northern hemisphere.

Unless...

The environment they're in simulates the oncoming of fall.

I doubt it though.

I believe it's:

1. The urea that has built up in the potting media. Urea usually breaks down in soil due to microbes. Without those microbes, urea remains very stable (this is why it was used as a component of the nitrogen in fertilizers to begin with).

2. Quite possibly root damage. Especially if you're saying there's some moss around the roots.

3. The tap water. Unless you know what the contents of your water is, there's probably a high level of dissolved minerals or very high levels of chlorine in there that can cause even the most mineral tolerant and chlorine tolerant orchid to get leaf tip burn.

The chlorine is the easy one to take care of. Just fill a bucket with the chlorinated water and let it sit for no less than 24 hrs. The chlorine will evaporate.

The dissolved minerals is a whole different story.

urgh, drat. It's odd that none of my other orchids are having this reaction though >.<

Any urea free fertilizers you could suggest? I'm just using the generic one I use on all my houseplants.

As for the dissolved minerals... hmm... I think we sell bottled water really cheaply at the grocery store I work at...

I might as well go for it since we're talking about it. While it's unlikely, is it possible I triggered it into going deciduous? How would I have done that?

Well...

There's always the MSU fertilizers.

I don't know if you guys have the Home Depot or not, and I most certainly don't know if any of the garden centers in your local hardware stores carry this particular brand of fertilizer.

But...

G & B Orchids fertilizer is a good one too.

Of course you can order this from them too. Look up G & B Orchids.

I believe Grow More brand has some urea free formulations.

There are a few others as well, but right off the top of my head, I don't know them all.

It'll work.

Shorter daytime length. Lower intensity of lighting. Cool temperatures (60 F to 75 F/16 C to 24 C). Fairly long periods of drought. No fertilizer.


I would also remove the moss from the roots.

Any other options other than buying bottled water for my 'chids? >_>

Definitely nothing I did then to make it go deciduous. It's near a south-facing window for Heaven's sake.

No one seems to like sphagnum moss >_> What would you suggest I grow in as a replacement?

Distilled water.

Go to a water store.

If the local supermarket has those water machines, then that's another option. Although I'm a little iffy about this one...

Actually, I speak for myself on this, and it's not true.

I do grow orchids with moss, just not all of them.

Sphagnum moss is not always appropriate for certain orchids.

If you pull up a picture of Dendrobium nobile, they are hardly found on trees with any kind of moss. Most of the pictures I've seen them in in the wild have shown them to grow on barren tree trunks or tree trunks with lichens, not moss.

Dendrobium nobile - 11 on Flickr - Photo Sharing!

Urg, so do not want to spend excess money like this >_> (Sorry, for moaning like this. I'm just really tight with money and will debate for twenty minutes on whether or not I want to eat. So spending like, a buck for a bottle of water for the plants seems terribly wasteful)

Ok, so they grow in barren trees, so taking that into account, that means that they don't retain a lot of moisture around their roots?

Which suggests something like bark I would assume?