Help with Black Spots on Vanda Roots
 

https://plus.google.com/photos/11650...49425921087217

Hello,

I am new to the orchidboard. I just purchased 2 blue vandas (Pachara Blue and Rober's Delight Black) from San Francisco Orchid show two weekends ago. I am in need of some help with growing them.

My current problem is that, each day there are a couple roots with new black spots appear at points where the root bends. These spots are dry and shriveled and then soon the entire root is turning yellow and increasingly shriveled. Please see above picture link.

Are these black spots mold? If they are why are they dry and not soft? Is the problem that they are too dry?

Here is my current culture condition:
63-66oF at night; 66-78oF during the day.
Hang by a bright south facing window
humidity is 53%-77%
I water them by immerse in a bucket of water for 15min
1st thing in the morning. Then 3 times at night with 1hr in between (3 times because they looked so dry and more roots start to shriveled).
The roots are white and turn bright green as soon as they are immersed in water. When hung back by the window, it takes only about 1hr for them to dry and turn back to white. (at night)
I change to a new bucket of water every day, and I fertilize every other day.
The plant had 4 new flower buds when I purchased them, and they open within a week. (Never seen buds grow and open so fast.)

Please help! How do I keep them healthy and stop the roots from dying?
1) is the problem too dry?
2) should I put the root in vase I as I seem some people do for vandas to keep the humidity higher during the day?
3) did I over fertilize? Maybe that was why the buds grow and opened so fast?
4) How do I promote new roots?


Thank you
Newbie2012

I only just acquired my first Vanda 2 weeks ago. But I suspect it could be some fungus related to watering multiple times at night. Cool, dark and wet = fungus problems. From what I have always read and done, you should never water your orchids (or most plants) at night fall. They need to have warmth and drying quite quickly and in the dark and cooler temps that won't happen. My Vanda is rather dehydrated and the leaves a bit leathery but I have been soaking it for about 1/2 hr every morning and it is just starting to perk up I think.

Others may have some ideas, but I would stop the night watering for sure. You could maybe mist the roots early in the afternoon once or twice. Using some K-L-N rooting hormone or kelp (seaweed) in the water would promote root growth.

Silken is correct. No watering at night, and it is fungus on the roots and that leaf. Increase air movement. Get these 2 fungicides if you can, ASAP, Dithane and Thiomyl (sp.?). Follow the directions for dilution and use it weekly for 3 weeks, then monthly after that. This will hopefully stop the fungus, but you may find that your new Vanda has been set back quite a bit, hopefully not though. If so, don't be discouraged, just get a new one at your next chance and start again with more experience under your belt. :)

Agreed. No watering at night. In fact I think you are watering too often. Once should be enough. I had the same problem with a bare root asco I bought a couple of years ago. I have found the bare root vandas in the home can be tricky. You might consider putting it in a basket with a little loose medium to hold so humidity. I use large lumps of charcoal and a little sphag in mine. Then you only have to water when the sphag is dry, which should be no more than a week at most, and ideally a few days.
Vase culture is also an option.

I think you work too hard for your vandas. Give yourself a break, and instead of soaking the roots multiple times a day, find another way of increasing humidity. Maybe you can place the vanda into an empty glass jar? I have read that this method is applicable in your area where humidity is low.
If you really want to soak the vandas, just dunk it for 2 mins to get the roots wet, and dish it out to dry. Soaking longer will drown the roots. Vandas roots are thick and fat with much velamen, designed to sponge up lots of water, so you don't need to soak it for long.
If your vanda is dehydrated and needs more water, they will tell you by sending out more new roots. So sometimes, it is better to just leave them alone.

From what you are saying, you are watering too often. I live in Jamaica and I water twice a day when its a really hot day, and once if the day is cool. I usually water between 7-9 in the morning, and between 4 & 5 in the evening on those hot days. That is sufficient; and my vandas are all outside. You must remember that they are epiphytes and have those long roots to capture any moisture occurring in the air. They don't mind drying out at all, just don't leave them without water for multiple days unless its in cold and moist weather.
All left for you to do now is systemic spraying for fungus once a week for 3 weeks and once a month every month thereafter as Gage said.
Good Luck!

The white velamen on the roots is designed to capture moisture from the air, I think you are too worried that when they are not green (white/grey) that it doesn't have enough water, but vandas are well designed to hold water really well. Seeing as you have a fungus problem on your leaves and roots, you'd probably be ok with only watering every second day

Thank you very much to everyone for their comments. I will reduce watering to 1 time a day at first thing in the morning. I also purchased an evaporative humidifier for them. It basically is a fan over a tray of water. So hopefully this increase humidity and air flow.

Did not find the Dithane or Thiomyl at Orchard Supply, but I did found Neem Oil extract as fungicide. Does anyone have experience using it on orchids? And in general when one apply fungicide, does that count as the daily watering, or do you do two watering, one with fungicide in water, and one with pure water?

Thanks
Newbie2012

The water will wash off the fungicide, so give the fungicide a day to set on the plant.

I may be wrong on this, but I think I remember reading somewhere that neem oil will suffocate your vanda. The reason why they are in baskets and grown without media is because the roots need to breathe.

I just wanted to reiterate that while you may need to work on the humidity and general culture, the most important thing right now is to allow your Vanda to dry out very very very well between waterings to slow the progress of the fungus (and treat it with fungicide). You can always increase watering to what makes sense for your environment later, but these next hours and days of drying are crucial for slowing the progress of the infection. If you are still looking for chemicals, start by cutting away highly infected roots and leaves, and spray it down thoroughly with Listerine mouthwash, which will both disinfect to a degree and help it dry out initially.

Also, check out Ray's website for some quick home remedies: http://www.firstrays.com/remedies.htm