HI,
It could be bacterial but I truly believe that bacterial problems only affect weak orchids.
Orchids that have been fertilized well are less likely to get bacterial infections and are able to prevent them taking over.
It could also be a deficiency, I am thinking in particular of either calcium or potassium as the culprit.
Potassium can creep up after many years particularly after the orchid has just invested lots into flowering.
The most important to preventing a deficiency is making sure you feed with the right ph. Over 7 is too high long term. PH should be 5.8-6.5
You can think of adding some phosphorus or a general bloom booster to replenish its reserves
It could also be calcium but calcium is fairly easy to determine, you just check the nutrient bottle, the calcium content should always equal your nitrogen amount so if you have 12% Nitrogen your Calcium should be roughly the same like 10%. If so then it is not going to be calcium related but if your fertilizer does not mention calcium or much lower content than the N in the bottle then your calcium is too low
Have a read through this article:
https://www.aos.org/AOS/media/Conten...psisPart_2.pdf
It mentions the best ratio for growing phals is 4-1-8
So something like 200ppm N, 50ppm P and 400ppm K has been found to be ideal.
As we can see phals like a lot of K according to latest research
I found this most interesting re-reading that article:
Quote:
All phalaenopsis planted in a bark
mix and lacking potassium eventually
died.
|
Quote:
Continuous application of nitrogen
ensures flower longevity, but does not
increase flower count after the spikes
have reached 10 inches (25 cm) in
length
|
Quote:
Potassium at 200 to 300 ppm
ensures high flower count and maximizes
flower size.
|
Hybrid Mode
