Vanda leaf discoloration-strange!

[orchidaddict789]

I have two ascocendas for my "experiment." On one plant, the leaves are showing strange yellow blotches. The blotches are circular (well, mostly), and some have a brown spot in the center. The photo isn't very clear--I can't seem to get the contrast high enough. Most of the discoloration is on one leaf, but on another leaf, there are several yellow spots the size of pinheads.

I've been growing them inside a glass bowl, and once a day, I fill the bowl with water, let the roots soak for a few minutes, and dump the water. I've noticed that many roots have started growing again (when I got the plants, the roots were pretty dry and inactive). Only the leaf color worries me...

I'm not sure what's wrong with the leaves. Fungus, maybe?

[orchids4me]

Humm that is strange. Is that bowl in a window? What time of day sun is it getting? Is the plant getting air flow. Misting and to high of humidity can cause fungal problems and wrong time day misting and to direct sun can cause burn is to why I ask water beads act like magnifying glass and burn spots can occur and with low air flow it won't dry quick enough.
Emmaye

[delphiguy]

How do you grow this? in terms of light? and why grow this one in a glass vase?
although this way, the roots get high humidity, the roots at the same time cant breath.
Anyways for the discoloration of the leaf, i wouldnt be worried much, happens to most
of my vandas tho they are grown outdoors exposed to elements... i would still apply
fungicide just for measure.

[Brooke]

I wouldn't worry about the discoloration. It isn't a fungus because it is inside the leaf - it is probably nutritional.

Emmaye it is an old wives tale that water spots are magnified by the sun. Water evaporates before it can magnify anything and cause burn spots - think hot afternoon, summer storm pops out, strong sun comes out - there wouldn't be any foliage on earth that wouldn't be spotted if water + sun did damage.

Brooke

[orchidaddict789]

Thanks everyone for the replies! They're near the windowsill facing east, so they get morning sun. They're in a bowl because I read on another forum that people were growing vandas in vases. I wasn't sure how it would turn out so that's why I decided to try this experiment. Maybe there's too much humidity or something?

Yes, the yellowing's inside the leaves. I only use light fertilizer after every couple of waterings...maybe it's too little?

I sprayed with fungicide just in case. The yellow is slightly more intense, but isn't spreading (which is good).

[digitalgate]

i agree this is minearl deficient , mostly likely magnesium and calcium. Try Epsom salt over the root area and see the leave colour change instantly!.