Yellowing Vanda
 

Hi,
This beauty was just in bloom and seemed happy (see last picture). I cut off the spent spike and a week or so later one leaf showed some yellowing at its base. The leaf was in the middle of the plant. I cut off the yellow portion of it but looks like the leaves above that leaf are yellowing too. Seems like the stem has brownish look to it where the leaf started yellowing too. I am so sad about this plant because it’s been doing pretty well. Growing new leaves and had nice root system too.
I water it by dipping it into a basin full of water for 20 minutes or so. Fertilize once weekly by spraying roots with 20-10-20 fertilizer diluted gallon to 1 tsp fertilizer. What do I do with it now? How do I save it? Thanks!

It looks like some damage occurred, and it may not progress, so I’d do nothing special and just keep a close eye on it.

If I may express some other thoughts:

That root system doesn’t look so great to me. A few active ones and more that aren’t. In my opinion, that’s kind of a strong fertilizer concentration to spray on and let dry, which is what your technique results in. You’re somewhere over 250 ppm N. Personally, I’d soak it once a week in a solution half that concentrated, and I’d seriously consider adding KelpMax to that monthly.

Your regimen sounds really similar to mine except, I add very dilute fertilizer to the soak water and just let it soak overnight. I also use Kelpmax irregularly:maybe every other month or so. After the first Kelpmax use all of the roots started growing and have never stopped and it’s constantly pushing leaves.

In terms of the leaf yellowing, with my Phalaenopsis, when I see something similar I put a bit of cinnamon down in the leaf axel to dry things up and hopefully make it less hospitable to ant fungi or bacteria trying to establish.

I should have specified that I spray that concentrated fertilizer once a week not daily. I think you were the one to recommend it in the past when I asked. So should I do half that concentration now?. Also the roots get inactive for me in the winter as it’s cold and dry. They get back to action in the spring. I will try KelpMax as you recommend, I have some. Thank you Ray.

---------- Post added at 12:03 PM ---------- Previous post was at 12:01 PM ----------

Thank you Alice. I will try the cinnamon.

I can’t imagine that I’d recommend that concentrate a solution for regular use. That’s probably the highest level I’d ever recommend, but only if someone was so lazy that they only fed once a month.

In my opinion, spraying that on the roots might be more damaging than soaking. (Bear with me a moment... “Thinking out loud”.). With soaking, the velamen and interior of the roots gets pretty well saturated. A spritz of the roots, on the other hand, really only wets the velamen, and as it dries (more quickly than a saturated root would) the unabsorbed salts concentrate.

I could be totally wrong...

I don’t know Ray, I may be confused. So I apologize for that. I had many recommendations so I don’t remember who said what anymore.
So if I fertilize once a week by spraying roots should I do 1/2 teaspoon or 1/4 tsp per gallon? Thank you

Where the yellowing is occurring, this is where I would spray that whole portion (including the brown patch) with a systematic fungicide.

Does this vanda get a decent amount of air-flow all around the leaves and stem in the growing area? Good air-flow around roots, media, leaves, stem can help avoid issues like this.

Also - what media are you using to grow your vanda? For my vandas, I grow them in scoria.

Around the first day of each month ----- I use a water wand to spray weak liquid fertiliser (mixed with my water) into the media (and the roots that are either in the media and on the media's surface). If there's any left-over water/fertiliser mix in the spray container, then I just top up the container with water (to give an extremely weak fertiliser) and use up the rest of it - basically regular watering.

The next two weeks or so will be regular watering - no fertiliser. Then ---- in the middle of the month, I apply a similar procedure --- except it's cal-mag application (rather than orchid fertiliser). Then regular watering occurs from that point up to the end of the month, and the fertiliser gets applied again around the first day of the month.

With my vandas growing in scoria with good drainage pot and good air flow in the growing area, I'm able to avoid having the watery slimey darkish look of some of those roots in the photo - which is not necessarily bad - but I prefer to not have the roots of my plant in that state.

Once a week - 1/2 teaspoon of that 20%N formula per gallon in the soak water, not as a spray.

Mine grows bare root. Roots are not slimy. They are just inactive. And yes I believe there is plenty of ventilation around the plant. They are hanging on the curtain rod in my living room area. Thanks for the recommendations.

---------- Post added at 09:02 PM ---------- Previous post was at 09:02 PM ----------

Thank you Ray.

Most welcome Irisha. If the vanda gets comfortable temperature, comfortable lighting levels, and good air-flow around the whole plant, and the required supplements, then it really cuts down the chances of that sort of yellowing and rotting issue.

If it gets too cold and/or still-air for relatively long periods of time, then it could invite some nasties.

One item that maybe a lot of Australian orchid growers have on hand is Yates anti-rot phosacid. I don't know if anybody uses it (or similar) outside Australia though. But - if you can get your hands on some - eg ebay - then it could come in handy sometime.