Roots shrink/dry out on Vanda hybrid (strap leaf type)

[anderslu]

Hello all,

We're a couple that for the last three years or so have become more and more enchanted by the beauty of the
different orchids out there.

About a year ago, we fell for the temptation and acquired a Vanda of unknown origin, all we know is that it's a strap-leaf type hybrid, probably with blue flowers (we never saw it bloom). The P.O. believed the plant had once been used for harvesting and selling cut flowers as it was quite large, approx 14 pairs of leaves and two shoots, approximately 15 cm and 10 cm respectively.

Already when we bought it some of the roots were dark gray and wrinkled, and didn't seem to swell when watered. The indoor climate in Sweden tends to be very dry and dark so we use supplemental lighting (60W CFL) and water every other day during winter, almost every day during summer. Half strength orchid fertilizer in every watering during summer, quarter strength during winter.

We have cowardly kept most of the roots but over time more and more of the roots have taken on the gray, thin
and wrinkled appearance, and the mother has lost seven or so leaf pairs, rendering it quite ugly. There are a
few roots emanating from the younger shoots that seem healthy enough, but we don't know whether they would
survive being cut off from their mother already.

There is also a thin, light green tangle of new roots that have grown from the mother, they look almost like
some sort of emergency response in order to provide the plant with water despite the unhealthy root system.
Does anybody know what these are, will they eventually become thick roots as well?

To top things off, we just returned from a two week vacation during which it turns out that the Vanda shoots and roots has received a lot of direct sunlight, and the watering system somehow failed. As a consequence, our dear plant looks worse than ever! (see photos attached to this posting).

Sorry for the long post, we have so many questions and just hope that we can save our dear Vanda!

[King_of_orchid_growing:)]

You definitely have a shot at saving these.

The green roots are a good sign.

If you're able to remove all the dead roots without ripping the plant off the basket, I suggest doing so.

The younger plantlets look like they have sunburn, how did that happen?

Anyways...

Vandas require a lot of moisture, especially if you're growing in a dryer area. Moderate humidity of about 60% - 70% or higher is good, and watering everyday will help it out.

Because I don't know what the flowers look like, I hesitate to say what kind of temperature range they'd do well in. If it has any Vanda sanderiana in the heritage, it's a warm grower. If it's got Vanda coerulea, it's a cooler/intermediate grower, but can handle warmer temperatures as well.

[anderslu]

Hi and many thanks for your swift reply, we too have thought of removing all dead roots, but the question is how can we be certain which roots are really dead?

The sunburn occured during our two week vacation when we left the plant outdoors without any attention.

We try to keep moisture at 60% minimum but during winter it rapidly falls below 40 or even 30 percent when we miss out on one of the several daily sprayings. In summer we keep several windows open most of the time and humidity stays comfortably between 50 and 70 percent.

The seller was of the opinion that this Vanda is suitable for our indoor climate, not requiring tropical temperatures or levels of humidity.

We read about some other Vanda owner that had successfully cut off all the bad roots, covered the remaining roots and leaves with a solution of sugar and fertilizer and then hanged the plant upside down (!) until new roots were sprouting. Any ideas on this advice???

Originally Posted by King_of_orchid_growing:)

You definitely have a shot at saving these.

If you're able to remove all the dead roots without ripping the plant off the basket, I suggest doing so.

The younger plantlets look like they have sunburn, how did that happen?

Anyways...

Vandas require a lot of moisture, especially if you're growing in a dryer area. Moderate humidity of about 60% - 70% or higher is good, and watering everyday will help it out.

Because I don't know what the flowers look like, I hesitate to say what kind of temperature range they'd do well in. If it has any Vanda sanderiana in the heritage, it's a warm grower. If it's got Vanda coerulea, it's a cooler/intermediate grower, but can handle warmer temperatures as well.

[King_of_orchid_growing:)]

Sugar water can give the plant instant energy. But it won't absorb a lot of it.

The remaining sugar is going to be left on the surface of the basket and the roots. If you have problems with ants, well...that goes without saying.

As for hanging upside-down, I don't know what that would do. Vandas grow upright and climb up tree branches and tree trunks.

You can google image Vanda coerulea in situ and you'll see how they grow, there's only one pic I know of and it's the same one I post here on the OB in older posts regarding Vandas.

You'll know if the roots are still alive when you water them and they still turn green. If they're shriveled and they stay dark brown and black, they're most likely dead. Snap a few that look dead off to check. You gotta wet them to know. When you cut them you should wet them as well. If you're working with the roots always wet them. Orchid roots are a bit more bendable when they're wet. Cleaning off dead roots from a plant prevents pathogens from hiding out and causing more problems. The roots also get a chance to breathe, as orchids breathe mainly from their roots.

[nenella]

An Idea could be to 'double up' on your watering regime ie: wet twice a day to keep the roots a healthy green - leaving them time to dry out as well..
A good method of finding out which roots are good and which ones are completely dry/dead is to soak the roots for even up to 6-8 hours. The live roots should definitely have plumped up in this time. If you are still not sure of a particular root start cutting from the bottom of a root up (just in case the root is green in the centre once you cut)At least you will limit the damage by not cutting off any still viable roots. I would also then soak in a rooting hormone to induce more new roots. I am sure this is more than savable! Good luck & let us know how you get on.

[anderslu]

Thanks for all the good advice so far! It sounds as if it's time for some serious surgery, to get rid of all the bad roots. I ordered a rooting hormone, too, as I've read that the Vanda can grow new roots from the bare stem (does that apply for hybrids?). Someone thought it would be best to scrape off all brown remnants of the dead leaves along the bare stem before applying the rooting hormone in order to stimulate new root growth the most. Any thoughts on this?

[King_of_orchid_growing:)]

Don't scrape off the brown parts of the stems where the remnants of the old leaves were. You'll injure the plant. Cut off the remnants being careful not to strip living tissue off the stem. The stem looks dead, but it's clearly not, as that's why you have two basal kheikis on the mother Vanda.

Apply the hormone onto the exposed surface of the stem.

The hormones should not be in powder form. They should be liquid so the plant can absorb them. From what I understand a synthetic plant growth regulator abbreviated TDZ works very well for root formation. Quite possibly better than IAA or NAA.

I don't know at what concentration you should apply the hormones at.

[anderslu]

Okay, we'll go easy on the brown parts of the stem. After we've cut off the dead roots we plan on replacing the basket with a new one to let the newly formed roots find their way out. Also, we are thinking of increasing the light and water more often and use fertilizer more sparingly.

Any idea what the light green tangle is btw (most prominent on the last photo)? It looks like an altogether different sort of root? Will it eventually thicken and become like the other roots?

[Junebug]

The light green tangle in the last photo doesn't look like part of the vanda's root system. I would take a guess that it's a form of moss that has hitched a ride on your vanda.

[oliesmommy]

Spanish Moss, favored home of redbugs and snakes. On the banks of the rivers where my husband grew up it grows so thick on the trees they would use it to swing off into the river Tarzan style.
Don't think it will hurt the vanda may even help to keep the moisture level up which is probably why it was there in the first place.
Wish I could help more with the vanda but I haven't a clue. Good luck though.