Spotting on Stanhopea leaves

[Jill H]

My little Stanhopea recently developed these spots on it leaves. it was quite pot bound and I repotted it today.
Within the last 2 weeks, I think I splashed the leaves with water and put it right back under the lights (T5's)
Could this be sunburn or do you think it is a more serious problem
Thanks, Jill

[King_of_orchid_growing:)]

What are the temperatures like?

How bright is it being grown?

How much fertilizer are you using?

What kind of fertilizer are you using?

[Jill H]

It is under 4 T5 bulbs about 1 foot below bulbs
Tem 78 to 80
Jacks classic bloom booster 3-9-6
1/2 tsp per gallon
I've tried to upload a picture, but seem to being doing somrthing wrong.
Thanks

[King_of_orchid_growing:)]

This problem is nothing serious, but it looks very ugly.

Most Stanhopea growers know this problem very well.

It's usually caused by a variety of factors.

1. Fertilization.

This needs a bit of explaining.

Since I don't know how much you know about Stanhopeas, I may or may not sound very elementary to you.

Stanhopeas don't like strong fertilization. They're sensitive to too much of it. It's easy for them to develop leaf tip die back or leaf spotting as a result of this.

Be sure the fertilizer is also urea free.

Urea doesn't break down easily. It takes the right environment and the right kinds of microbes for the urea to become available to the plants. So if there are any traces of this left clinging to the roots of the Stanhopea and it doesn't start breaking down soon enough, guess what, it's leaf tip die back/leaf spotting time!

Better sources of nitrogen for orchids would be from nitrates or ammonia.

2. Watering using hard water.

Stanhopeas are sensitive to water quality. Water in low dissolved minerals are usually the way to go to get a pristine looking set of leaves on these plants.

3. Temperature.

While there are very few Stanhopeas that are actual cool growers or are temperature tolerant. Most of them are intermediate or intermediate to warm growing.

Growing in incorrect temperature ranges will result in leaf spotting as well.

4. Air circulation.

Stanhopeas like a fair amount of moisture in order to grow properly. Because of this, they need some air circulation to prevent suffocation and bacterial or fungal attacks.

5. Root damage from incorrect cultivational practices or being very careless during mounting or repotting.

Really?

Yes, it will cause leaf blemishes to some degree or another.

[Jill H]

Thank you so much, this was a great help. I know now it was over fertilization. Some of my phals are showing yellow leaves. I water with R/O and have a ceiling fan going on low all day. Just ordered some MSU fertilizer. I plan to flush vigorously for several weeks with water only. I was able to get the picture into my album "trouble" if you care to look, but I'm sure it looks quite like what you suspect. Again I thank you so much

[King_of_orchid_growing:)]

You're welcome.