Phragmipedium besseae leaves turns red

[moria0672]

Thanks to all for the suggestions

Originally Posted by Bolero

Actually I think you have a good point. In Australia is very good and our water doesn't need treatment. That would explain why we don't see this issue from what I've seen anyway. If the water is high in minerals maybe this is a normal reaction for the plant and you need to treat your water. That would also make sense.

For all my orchids I exclusively use rain water...I have a 1.000lt tank that grant me 365 days of rain water...so I don't think it's a problem of high minerals in the water...

[naoki]

If I remember correctly, Peter's doesn't contain Ca and Mg since it is formulated for tap water (not RO or rain water). But it's not the symptom of immobile elements like Ca (because the older leaves are affected). I think you are giving about 100ppm N every 2 weeks, which seems to be ok for most orchids. But you might want to consider reducing it.

Since I killed P. besseae with a similar symptom (long time ago), I'm not probably the one who should be saying anything in this thread. But I think the problem of mine was that the temp was too high. I was in warm North Carolina, and it grew ok in the winter, but get stressed in the summer (like yours), and it died.

[Bolero]

Interesting that heat causes that, I haven't had that happen to anything I have before but will be mindful of that in future with out summers.

[moria0672]

Originally Posted by naoki

If I remember correctly, Peter's doesn't contain Ca and Mg since it is formulated for tap water (not RO or rain water). But it's not the symptom of immobile elements like Ca (because the older leaves are affected). I think you are giving about 100ppm N every 2 weeks, which seems to be ok for most orchids. But you might want to consider reducing it.

Since I killed P. besseae with a similar symptom (long time ago), I'm not probably the one who should be saying anything in this thread. But I think the problem of mine was that the temp was too high. I was in warm North Carolina, and it grew ok in the winter, but get stressed in the summer (like yours), and it died.

Thank you Naoki for this new observation, but I don't think is a matter of temperature, the cooling system in maintains inside the greenhouse a max temperature of 29/30°C (reached in the hottest days, when outside we had 38/40°C).
About fertilizing, I normally use 2 teaspoon per 5 liters, I have no exactly idea the quantity in ppm.

[silken]

Originally Posted by moria0672

Thank you Naoki for this new observation, but I don't think is a matter of temperature, the cooling system in maintains inside the greenhouse a max temperature of 29/30°C (reached in the hottest days, when outside we had 38/40°C).
About fertilizing, I normally use 2 teaspoon per 5 liters, I have no exactly idea the quantity in ppm.

I am not familiar with that particular fertilizer but that sounds like a lot for just over a gallon of water. Are you sure it is half the recommended dosage? I have a besseae primary hybrid and several other Phrags and I have them all standing in an inch or more of water. I can't tell from the picture, but I wonder if it is being kept wet enough.

[Island Girl]

Originally Posted by moria0672

Thank you Naoki for this new observation, but I don't think is a matter of temperature, the cooling system in maintains inside the greenhouse a max temperature of 29/30°C (reached in the hottest days, when outside we had 38/40°C).
About fertilizing, I normally use 2 teaspoon per 5 liters, I have no exactly idea the quantity in ppm.

Wow, I think you might be over fertilizing, you said you use 20-20-20, at 2tsp per 5 liters (1.32 Gal)..... And with that, according to Ray's Fertilizer PPM Calculator, you are getting close to (if not more than, depending on your water) 600 ppm of nitrogen!

As an example, for 100ppm of N (I'm not sure what number you want for this orchid, I'll let the experts cover that!) you would want to use 0.38 tsp per US gallon; or 0.49 ml per liter.

[RosieC]

Originally Posted by Island Girl

Wow, I think you might be over fertilizing, you said you use 20-20-20, at 2tsp per 5 liters (1.32 Gal)..... And with that, according to Ray's Fertilizer PPM Calculator, you are getting close to (if not more than, depending on your water) 600 ppm of nitrogen!

As an example, for 100ppm of N (I'm not sure what number you want for this orchid, I'll let the experts cover that!) you would want to use 0.38 tsp per US gallon; or 0.49 ml per liter.

I'm not an expert, but for Phrags especially sensitive ones like besseae I would not go above 100ppm N. I use 125ppm N on most of my orchids (roughly) and I halve that for my phrags. My besseae hybrid shows signs of excess fertiliser at 125ppm N which is when I started halving it. Sometimes I use even less than half (I'm very rough in my measurements so tend to go on the low side for the phrags just to make sure.

[Nexogen]

Maybe is over potted, but I don’t like peat moss, is very acid (3.5 to 4.6) pH and I think is micronutrient intoxication.

[naoki]

Massimo, if your concentration is not a typo, I agree with others (Mary Lynn said 600ppm N, but isn't it about 400ppm N?). It could have caused root rot (too much salt in the media causes dehydration of root, and kill the root, which leads to "root rot"). So it might be a good idea to repot it (or soak it in the water for a long time to get rid of accumulated salt), then use much more dilute fertilizer. Lots of people are going with around 30-50ppm N (or even lower) for every watering. Also you should check if Ca and Mg are in the fertilizer since you are using rain water. If not, you might want to sprinkle granular (not the powder kind, which will be washed out easily) Dolomite Lime. I use about a pinch (1/8tsp or less) per a small pot.

Bolero, I'm not completely sure about the heat issue, but I think they do "prefer" cooler temp (than other Phrag). I hope other real Phrag expert will chime in. They can "tolerate" quite a bit, and people in warm climate seem to be successful. I'm guessing that modern P. besseae is less picky due to artificial selection for a while. I'm in a cooler climate now, so I decided to try Phrag. d'allesandroi (closely related to P. besseae) this year.

[euplusia]

My immediate first idea is too high temperature (also eventually caused by solar irradiation) as this is what I know from my phrags. So I cling to Naomi and Bolero.
Autumn and winter are a cure by nature.