Suggestions on saving this rootless Vanda tip cutting

[cuckoo]

I bought four BS Vandas (Rhyncostylis/hybrids) from Krull Smith May 2021 (one in bud). I transitioned them from bare root to lava rock in terracotta pot. They were left outdoors with partial sun exposure and of course rains. A couple of months later. while one of them (Perreiraara Rapeepath) was in spike, it suddenly developed what I determined to a bacterial rot (wet translucent spots on leaves followed by yellowing and browning, healthy fat green roots turning brown/black from inside. Within days the Vanda died despite all efforts to save it by cutting off infected parts, liquid copper fungicide treatment (supposed to work on bacteria as well). The infection got to the lower stem and then the crown even though I thought I had cut off the infected stem, leaves and roots. See the sad story here Sudden fungal/bacterial attack on my Vanda in spike

Now I have serious issues with another one of the lot (Rhynco. Coelestis pink). I had gone away for a month and left it in a SE window in Oct 2021. I had put the pot in another pot with a bit of water at the bottom of the outer pot but not touching the inner terracotta pot that the Vanda was housed in. Anyhow, it appeared fine when I got back but a few of the very healthy fat newer roots had turned brown and then a couple of leaves at the bottom turned yellow in the next few weeks. When I examined it closely and cut off the brown roots and yellow leaves, I suspected that the stem may also be infected. Eventually, I cut the stem at the base and found it to be rotten. I cut off the infected stem and cut some more of the stem upwards (total 1-2" length) leaving only a soft green stem tip part (1-2" length) with a few leaves.

The remaining bottom somewhat less infected stem with the roots had a Kieke and I hoped it would live but it withered away soon. So, now I have the stem tip-I treated the cut wound with cinnamon and left it to dry. I have been letting it sit among the foliage of some of my jasmines for now, mostly out of sun. The question is what I should do to help it develop new roots without risking the return of the fungal/bacterial infection that caused the current state of affairs. One would normally provide some moisture via potting media (bark or such) for the stem to root and possibly an enclosure to prevent the leaves from drying such as a plastic bag. However, given the infection history I am not sure those steps wouldn't just kill the poor thing.

In fact, I am now convinced that my remaining two healthy vandas from Krull also possibly infected ticking time bombs. They both have lost some bottom leaves at the base at different points in time and aren't growing much at all for a while now. I am convinced that the infection was inherent in these vandas. I have a couple of Vanda seedlings fro a different source that are perfectly healthy under similar conditions.

[estación seca]

Where do you live? What were the growing temperatures outdoors that the Perreiraara Rapeepath experienced? How often did it get rain? How often did you water it when there was no rain?

The Rhynchostylis coelestis is not infected with anything. It is dead from not getting watered enough. It can't go a month without water. The top has a tiny chance of rooting if the stem is mature, but I don't think it is.

Where are the two remaining Vandas from Krull growing? What are the temperatures there? How much light are they getting? How are you watering them?

[cuckoo]

Where do you live?

New Jersey, zone 7b coastal, overlooking the lady liberty

What were the growing temperatures outdoors that the Perreiraara Rapeepath experienced?
So, it was May-early july, temps were relatively mild, neither cool nor hot. I would think somewhere between 60-80.

How often did it get rain? How often did you water it when there was no rain?

It was watered every week/ten days when it wasn't watered by rain, it was potted in lava rock in terracotta orchid pot. Watering was sufficient based on turgidity of leaves and how quickly the roots turned green upon watering. It rained probably 5 to 10 times a month.

The Rhynchostylis coelestis is not infected with anything. It is dead from not getting watered enough. It can't go a month without water.

The stem above and below the dark brown/black stem part was green. The roots turned green quickly upon watering. The leaves were and are still fully turgid and not showing any signs of dehydration/leathery appearance. I would know a dehydrated orchid from an infected one. I am not in the habit of destroying my plants by imagining infections. There were other similarly sized vandas in identical conditions which are live and well. A vanda would dehydrate before dying. Death via dehydration means dried up dead roots and dehydrated/crisp leaves.

The top has a tiny chance of rooting if the stem is mature, but I don't think it is.

Great!

Where are the two remaining Vandas from Krull growing? What are the temperatures there? How much light are they getting? How are you watering them?

They are in east/SE windows with supplemental light. They are potted as described above in lava rock. They get watered every week/ten days. I understand that people who water their vandas everyday think they will die if not watered that way but potted vandas with some water retentive media do not need daily watering. Temperatures are 60 to 70.

---------- Post added at 08:44 PM ---------- Previous post was at 08:41 PM ----------

I understand if people have good experiences with Krull and would rather blame me rather than Krull but I do not make these observations lightly and am not brand new to growing orchids.

[King_of_orchid_growing:)]

1. Lava rocks tend to retain water quite well. You may not have noticed, but I suspect the roots rotted because it was unintentionally overwatered. The top of layer of lava rocks may have looked dry, but the ones at the bottom of the pot may have stayed quite wet for several days, especially in a terra cotta pot.

2. Most terra cotta pots have poor drainage due to lack of sufficient holes that are strategically placed. It is possible that the water at the bottom of the pot didn't really drain out completely. Some of it may have been at the bottom towards the inner edges of the pot where there are usually no holes.

To make sure the water is not sitting at the bottom, I recommend tipping the pot over to have the water drain from the top.

3. Vandas may require a good amount of moisture, but the roots prefer to dry out fairly quickly.

4. I didn't catch how often it was raining. It was implied that it may have been raining for a short number of days (possibly even consecutively). Are you able to be more specific with this detail?

5. Although every seller has sent some bad stock before, I don't think this may be the case unless the decline happened very shortly after receiving. Or if you had photographic evidence of having to receive a plant in poor health immediately upon receipt.

If the decline happened about 2 months under your care, then it is highly probable that it has something to do with your techniques/methods.

6. Everyone makes mistakes. If you made quite a few this round, it is ok to admit it. As adults, there's no reason why anyone here would talk ill of you for it.