Leaves with soft spots

[freslie]

I repotted this plant 3-4 months ago using Phalaenopsis Monterey Dark Imperial Orchid Potting Mix (from Repot Me) and it has been doing well. I usually soak approximately once a week with tap water. The plant has been thriving and grown an additional leaf and has had healthy roots. For 2 weeks, using advice from another forum, I soaked with rain water. Soon after I developed problems all 3 of my orchids. This orchid has developed soft spots on 2 of its leaves. Suggestions as to what is happening?

Update: I checked the roots after soaking and they look like they have white fuzz on them. I have added 2 pictures.

[Mountaineer370]

First, welcome to the Orchid Board! You've told us and shown us with your photo the type of medium your Phal is potted in, and the type of pot. Both look very appropriate. I would be very surprised that changing from tap water to rain water for a couple waterings would have caused something like that to happen.

I'm wondering what the rest of your growing conditions are like. What are the temps and humidity like in your growing area? Do you grow outdoors, indoors, with supplemental lights, in a window with direct sun? Frankly, the first thing that occurs to me is that the large damaged spot you are showing us might have been caused by exposure to sun or a very hot light.

My posting here will push your question back to the top of the list where it will hopefully be seen by other experienced members.

[estación seca]

Welcome. I also think it looks like sunburn. Phals. are full shade plants. They never need sun shining on their leaves.

[freslie]

My plants are in a bay window with partial sun. The orchids are farthest away from the window and this phal has been in the same place for 2.5 years.

[camille1585]

Originally Posted by freslie

My plants are in a bay window with partial sun. The orchids are farthest away from the window and this phal has been in the same place for 2.5 years.

If your weather has been anything like here (overcast and rainy for weeks on end), if you suddenly have a couple nice days the plants theoretically could burn since they are not used to the light anymore.

How did you collect your rainwater? If it's coming from collection barrels that have been sitting full of water for a long time, a plant debris falls in, it's entirely possibly for it to be contaminated with plant pathogens.

Best course of action now would probably be watch and wait. If the spots don't progress further, then it was likely sunburn (this is assuming the get some direct light, you don't mention this). If the spots spread, it's likely a disease and you may need to remove the affected leaves.

As to the roots, the fuzz is normal. It's a sign of nice healthy roots, and the root hairs help take up water. I don't often see them on Phal roots, but they're generally in the pot where it's nice and humid.

[Ray]

The band across that lower leaf is very well defined, making me think "sunburn" as well.

[freslie]

Thank you for all the advice. I just used rain water out of a bucket. I will keep an eye on the phal and see what happens. And make sure it doesn't get direct sun. Which I didn't think it did, but maybe I've moved the other plants that were shading it.

[Mountaineer370]

Sounds like a plan to keep an eye on it and note if that spot grows at all. Is there any kind of a reflective surface that could have redirected incoming sunlight in any way? My cousin once almost had a house fire when sunlight came in through a bathroom window, reflected off a mirror on a shelf in the room, and caused a scorched spot on the wooden window ledge.

Eventually, that leaf will decide to turn yellow and fall off on its own, and unless the bad spot spreads, I wouldn't do anything further other than to care for the plant normally.

[Roberta]

I have also had "surprises" when the sun shifted or just had a bit of bad timing. I recall one time, I saw a burned spot on a leaf in my greenhouse, and totally couldn't figure out how it happened. One day, I just happened to be in there on a bright, warm morning, and caught unfiltered sun coming in a vent that had opened in the heat (earlier than usual) sending a beam of toasting sun onto the leaf for maybe 2 minutes (usually at that time the vent was shut at the time that sun was at that particular angle so the GH roof filtered the sunlight) As the sun shifts, what works in one month may be a problem in the next. Eternal vigilance...