Black leaves on vanda/neofinetia

[SundayGardener]

Yes, I am going to have to repot the ones in spagh. I discovered today that one of them is not doing well underneath the spagh. It is so hard to predict how long the moss will stay moist because the temperatues keep changing outside, and then the heating system fluctuates. And the water temperature is always lower than the aid temperature, so I really do not want them sitting cold and wet.

I finally attached some pictures. Ignore the leafless sad dendros in the background. I have a few with black top leaves, including neostylis Lou Sneary, and some recent acquisitions. I have others which are in exactly the same conditions, with no issues whatsoever. Same light, same media, same watering. I can't tell if this is too much light or something more insidious.

Also in the pictures are some microfiber wicks which are still in the pot but NOT being used (except for 2 plants). Those are leftover from when I had to leave and wanted to have a system in place for watering. Works great for some, not so great for the neos, but I have one tiny vanda that loves it.

[Shoreguy]

You state “Water temperature always colder than air temperature.”

What is your water source? If an indoor faucet, you should regulate the temperature to something comfortable to your touch, slightly cooler than lukewarm.

Frigid water temperature can cause leaf necrosis and could cause the problem.

[camille1585]

When I got my first Neos, I thought I was following the 'instructions' well by watering twice a week in winter, because the sphagnum was dry after 2 days. I lost all 3 to rot in the first winter, and was discouraged because I thought I had done everything right.

Fast forward several years, and I've now had all my Neos (in sphag mounds) happily survive 2-3 winters. This time, I picked up some tricks here in the forums. What I did differently: very, very limited watering in the winter. I only properly water them every 2 weeks or so (running only a small amount of water through the mound, rather than completely drenching it as I do in summer), never get the leaves wet, and water in the morning. The rest of the time I use a spray bottle every 3-4 days to get the mounds damp, but not wet. For a large collection this may be time consuming, but for my 10 Neos this takes only 5 minutes.

The key rule is to wait until the sphag is thoroughly crispy, inside and out before watering again. Early on I would remove the sphag mound from the pot to feel inside, but now I can tell by hand weighing the pots.

For all my orchids, in the winter I never water with ice cold water directly out of the tap. I always keep a full watering can ready so it's at room temperature when I need it.

[tundrabehr]

Sounds to me to be a bacterial infection. Water that is left in the growing tips of the fans is never a good thing. Especially when the temps drop at night. A good way to avoid this its to make sure to water early in the day so the leaves have a chance to dry . Also Good air movement is a definite must have.

[SundayGardener]

They are all getting a dry week this week.

I don't use tap water because our municipal well water is not terrific. I use RO from the grocery store with K-Lite. Sometimes I use tap water for the catts because the water has a high mineral content.

I can't use warm water from the tap because we have a water softener.

I do warm the water at the time of watering, however unless the media dries immediately, anything wet will cool off. I do have seedling heating mats, but all the neos are under hot T5HO lights or in a room that's pretty warm.

I've had 4 neos for over a year now, so this is their second winter, and they are just fine and dandy. They are in tree fern. I'll be moving the ones in spagh into tree fern or large bark (which has not worked well for me in the past).

I do try really hard to keep everything dry. I do have issues with either fungi or bacteria but have not been able to identify or narrow it down. This has gone after the dendros with a vengence but seems to ignore the others. I've used Cleary's with some success, everything else (I have quite an arsenal) seems to do more harm than good. I've wiped down my growing area with Physan repeatedly. I don't know what to say. I can get a brand new dendro, put it in isolation immediately, and within a week it will have the same spotting on the leaves as the other dendros. But I haven't seen this moving to any other orchid except maybe a catt or two, which did respond to treatment. The dendros just lose all their leaves and then taunt me with blooms and then the canes rot. That's a different story. The dark leaves on these neos don't look at all like what is happening with the dendros (but then they have different leave structures).

[Shoreguy]

Your situation is outright challenging. The only thing I can recommend now for the neos is use the larger bark only as drainage at the bottom of the pot and get some seedling bark to mix with the shredded tree fern, approx 80% seedling bark, 20% shredded tree fern.

I really don't know what else to say.

[estación seca]

I'm not an expert on Neos, but I've lived in Wisconsin. If I grew Neos there, in winter I would put them near a window in a cool room and be sure they didn't freeze. I would not water them all winter. I would not give supplemental light. Neos can go months without water in cool weather, and they won't rot. There's no advantage to trying to keep them growing in a difficult situation when they do fine with a cool, dry dormancy.

[Shoreguy]

I've never been to Wisconsin but have been successfully growing Neofinetias for approximately 50 years. By successfully I am not saying flowering all of them every season but always flowering some and some others never.

Thus I do not consider myself a Neofinetia expert since I am still learning but I feel knowledgeable enough to make suggestions in this forum.

I do not believe withholding watering entirely for the entire winter is advisable but recommend letting the medium dry out completely or almost completely. Only water in the morning on days forecast to be sunny and avoid getting any water on the leaves. If you do, use tissue paper or toilet paper to dry off any droplets remaining.

Also any plants with spotted leaves may not recover as the problem might spread systemically to healthy leaves.

I know there are reasons why some Neofinetia growers prefer sphagnum but considering your situation, I believe seedling bark/tree fern mix is preferable. Sphag is far trickier to manage watering.

[SundayGardener]

I will give them longer dry periods. I don't think I can go without watering them at all, especially now that (in theory) we are inching towards spring). When their roots get really shriveled up and brown I get nervous.

I only have 2 in spagh right now, and only 1 in a room where it gets warmer than 70 F. I don't think any room will be over 70 in coming days since we should be long past the polar vortex season.

I started out with one basic neo and it did so well that I decided to focus more on neos. I've tried different orchids to see which I can grow in my conditions, and the neo and neostylis I started with (and still have) were winners in the survive and thrive contest. Now I am re-evaluating, I obviously started out with hardy, easy-going (and also fairly large and well established) neos. I really like the appearance and compactness of neos.

Thanks for all the feedback! I do read it all and try to incorporate it and learn as I go.

The one beautiful neo that went belly up was in large chunk bark which is why I am nervous about bark. It has done me no favors.

[Shoreguy]

If you ever see the roots even starting to shrivel, you should at least spray them if the pot feels heavy, if it feels light water the pot. Total lack of watering or at least spraying for a prolonged period is not advisable even in the Winter as neos are not cacti.

In the winter I try not to let the pots dry out completely but only if forced to, I wait until a sunny day.

During the growing season, Spring, Summer, mid Fall, I water or heavy spray before the pots approach dryness. Once again, hopefully on sunny days.