Phalaenopsis Bellina - Brown stains on leaves

[Roma Oli]

Hello,

This morning I noticed brown stains on the leaves. I watered the plant on Saturday - my guess is that some water stayed on the leaves for too long and might have caused a bacterial infection. Do you know if that is the case?

I patted the leaves with hydrogen peroxide this morning, but now wondering if it is effective anymore since it was open for a while. I read that if it is a bacterial infection, I need to remove the tissue urgently which means removing the two top leaves (see picture attached), which is probably very stressful for the orchid.

Please advise.

Thank you so much in advance.

[estación seca]

That looks to me like heat or sun damage. Could it have been too close to an electric light or a sunny window? Bacterial spots are usually soft and weeping liquid. Water rots usually occur in the very center of the crown, not farther out on the leaves.

What are your ambient temperatures and relative humidity? What kind of light is it getting?

[Roma Oli]

Thank you very much for your quick response.

I recently moved the orchid to a southeast-facing living room tinted glass window. I used to keep it further away from the same window. I don't always monitor temperature and humidity, but it is 72 degrees now at midnight, so I assume it is much warmer inside during the day. The humidity is 44%. Last week and this week were also warmer than usual.

When touching the stains, they don't feel watery to me. The larger one feels a bit sunken, especially from the bottom, I can somewhat feel the boundary ridge of the stain. The smaller stain seems to have the same leaf thickness, just different color at the moment.

Thanks so much for the insight, hopefully, this is not as bad as a rot.

[Ray]

Sunburn.

In the wild, they are deep shade plants. More light is not “better”.

[DeaC]

I'm concerned about the yellowing crown. Am I wrong?

[Roma Oli]

Thanks so much again for your insights. I moved the orchid away from the window. I am really glad I wrote here before taking any action.

Regarding the yellowing crown, I think it was always much lighter in color than the rest of the plant, unsure if it was yellow. What would yellowing mean?

I attached a few pictures of the Bellina blooming two years ago (pictures 1 and 2). One of them shows the crown. When I purchased it, it was planted in sphagnum moss and I was advised to keep it, which I did. Last autumn it grew a new spike and was about to bloom, but I had to leave on a trip and left it under my friend's care. When I got back the bloom was dried off. It still had a spike and I was expecting it will develop a new bloom. It's been like that for half a year.

I decided to repot it two weeks ago - I realized it was lifting itself with the roots at the bottom of the pot. The leaves are not shiny anymore so I thought it wasn't happy. I was also surprised that it didn't grow roots in the moss - the roots were arranged all around the perimeter of the pot. There was just 1 rotted root that I removed. But I saw some sort of a white mold deep in the moss at the center of the pot. I removed all old media and potted in a mixture of bark and sphagnum moss (I keep most of my orchids in it). Pictures 3 and 4 show the repotting.

I took pictures 5,6,7 today.

I water it once a week with fertilizer and once a month with Kelpmax which I think does wonders. After fertilizer/Kelpmax, I also shower it.

Please let me know if you have any advice on how to improve.

[estación seca]

Around the outside of the medium is how Phal roots tend to grow in both moss and bark. Moss and bark are both good choices if watered correctly. Watering in moss is different from watering in bark.

In your current pot/medium combination you will probably need to water more frequently than you did in the moss. Water when the roots are almost but not completely dry.

Phals don't ever need sun shining on the leaves. They are deep shade plants. They have been shown to produce bigger and more flowers at around 1,000 foot candles / 11,000 lux rather than more. Flowering is stimulated by a 6-week period of increased light in late Fall, to 1,200 fc / 13,000 lux, after which they should be returned to lower light.

Day length matters for flowering. Being tropical plants they are best grown with nearly 12 hours of light per day. If they get a shorter day they may not flower. This may mean electric lighting in Fall/Winter/Spring in northern countries.

[camille1585]

That Phal looks great and very healthy, other for the brown patches on the leaves. Burning can happen very quickly, especially if the plant wasn't used to it. If it was/is a pathogen, you would likely see those patches get larger. When in doubt, a good trick is to draw a line around the patches with a felt tip pen, and watch if the patch grows outside the line.

Originally Posted by estación seca

Flowering is stimulated by a 6-week period of increased light in late Fall, to 1,200 fc / 13,000 lux, after which they should be returned to lower light.

Just a small correction, the main trigger for winter blooming Phals is a general decrease in temperature for 6-8 weeks. Increasing the light alone won't trigger spiking, but does improve the quality of the spike induction (more chances of double spikes or branching spikes).

Originally Posted by estación seca

Day length matters for flowering. Being tropical plants they are best grown with nearly 12 hours of light per day. If they get a shorter day they may not flower. This may mean electric lighting in Fall/Winter/Spring in northern countries.

This is not my (and many other people) experience with Phals in a northern country. They were flowering very well under natural daylight/daylength conditions (8 hours of daylight in december) before I got some supplemental growlights, and when I added lights the main effect I saw was a lengthening of the growing season. Spike induction usually naturally happens in the fall, when the days are still much longer.