Hot sunny day? LOL
Yup, but it seems to be quite strong. All the blemishes they got, appeared after the second spraying, so it might have been too much for some of the Paphs.Same stuff as EndAll.
Did you spray it during the evenings? If you spray it during the hot sunny day, it could cause blemishes on the leaves. Maybe that is why there are spots on your plants.
Forgot to ask, How long does it take your potting medium to dry out?
I'm glad that this is exactly what I'm doing at the moment. Insecticide has been used, now I'm waiting for a better fungicide to arrive and finish the job.Those last pictures suggest insect damage to me, too. I believe in the 'blunderbuss' approach - use everything! (insecticide and fungicide).
Is there a local orchid society meeting close to you? You could phone them and ask if there was some way an experienced member could look at your plants. You could also take a few to the meeting but leave them outside or away from the other plants and ask if someone could look at them.
The length of this thread shows that 'orchid' people like to help each other.
Those last pictures suggest insect damage to me, too. I believe in the 'blunderbuss' approach - use everything! (insecticide and fungicide).
The length of this thread shows that 'orchid' people like to help each other.
I've seen this in Phrag besseae. The leaf tissue seems to liquify on the inside, while the outside remains dry. It was a calcium deficiency. I solved the problem quickly by feeding with Phostrogen, which contains calcium and Magnesium. Nowadays, I use Calcium Nitrate and Epsome salts in my regular feeding schedule and I never see this problem anymore.
That is your thesis, but you have presented essentially no evidence that it is true.Problem with calcium/mg deficiencies, is that plants in the presence of even moderate K concentrations will preferentially take that up no matter how much Ca they are sitting in.
That is your thesis, but you have presented essentially no evidence that it is true.
That is your thesis, but you have presented essentially no evidence that it is true.
The old 1978 Cornell study has been discussed and presented before.
That one is actually based on orchids.
The Winkler and Zotz 2010 bromeliad study is another.
And you could look through a bunch of agri data for domesticated crop plants.
Not just a theory, but a well study plant physiology understanding.
And I have yet to come across any leaf tissue data indicating that you can force plants to take up Ca in presence of moderate to high K.
I've seen this in Phrag besseae. The leaf tissue seems to liquify on the inside, while the outside remains dry. It was a calcium deficiency. I solved the problem quickly by feeding with Phostrogen, which contains calcium and Magnesium. Nowadays, I use Calcium Nitrate and Epsome salts in my regular feeding schedule and I never see this problem anymore.
but ammonium will also inhibit uptake of K so the matter is probably more complex than we think.
As an example, take another look at andre's Paph niveum:http://www.slippertalk.com/forum/showthread.php?t=32826. This is fed with hydroponic fertilizer which in every sample I have seen is loaded with K (usually as high as the N content) I don't see any problems with this plant!
.So compared to the "weakly weekly" program in a bark based matrix his total K application is very low even if the actual fertilizer composition is comparable to MSU
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