Time to throw in the towel...
- Thread starter The Mutant
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Paphman910
Well-Known Member
I meant that if the plant was sitting on a windowsill and the sunlight hits the plant and causes the leaves to get quite warm even on a winter day
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.
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.
The Mutant
Well-Known Member
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.
It totally depends on the plant in question, since they all are in more or less different sized pots, and some dry faster than others (for no apparent reason that I can see), while others take their sweet time. I would say at least all are watered once a week, the smaller Paphs more often since their pots are so small (5 cm or 2"). I still need to learn how often to water them though.
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.
I do have a meeting close to me, but I've forgotten to apply for membership, and I really don't want to take my Paphs out into the blizzard. And since I'm such a genius and removed all the suspicious looking tissue, there's nothing to see, except some heavily pruned Paphs.
papheteer
Well-Known Member
Great advices have been given already. I have only one to add. Try and give them the best growing conditions. Its never gonna be perfect. Don't fuzz over them every second and expect the worst to always turn out. "Ignore" them and hope for the best. Works for me.
Rick
Well-Known Member
I agree
Those random spots all over the leaves are not typical of rots that frequently all run up from the base of the leaves. That funny pimpling also looks buggy rather than bacterial or fungal.
Excessive bug damage could set up a plant for secondary pathogens kicking in, but in some ways it looks more like "bruising" caused by bug bites.
Rick
Well-Known Member
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.
So the Blomstra additions would constantly negate boosted Ca/Mg with either potting mix ammendments or liquid supplements.
Mutant, if you think that growth/leaf color is poor with straight K lite, then boost P and Mg instead by using dilute use of Dynagrow Bloom boost Mag Pro. That will keep the K down will boosting P and Mg.
D
DavidCampen
Guest
That is your thesis, but you have presented essentially no evidence that it is true.
Rick
Well-Known Member
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.
Rick
Well-Known Member
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.
D
DavidCampen
Guest
Not even a theory, just your bizarre and baseless thesis.
SlipperFan
Addicted
Rick, don't take the bait.
Stone
Well-Known Member
I've read that high amounts of K (that is grossly imbalanced amounts) can inhibit Ca and Mg uptake. Problem is that I have yet to see a definative report that shows what constitutes ''grossly imbalanced''
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!
Also ammonium will inhibit Ca and Mg uptake but it will also inhibit uptake of K so the matter is probably more complex than we think.
Rick
Well-Known Member
I don't have the whole paper (since I can access it only for $40) but this could be a good read:
Calcium-Related Physiological Disorders of Plants
F Bangerth 1979
Annual Review of Phytopathology Vol 17: 97-122
Excerpt from the free access introduction.
" Many of the physiological disorders afflicting both storage organs, such as fruits , certain vegetables, roots, and young, enclosed leafy structures are related to Ca content of the respective tissues. Improving their Ca content normally diminishes the occurrence of the respective disease. Shear (157) has listed more than 30 Ca-deficiency disorders and this list probably will be extended as research in the field proceeds. These disorders are believed to be due to inefficient distribution of Ca rather than poor Ca uptake. This problem is illustrated by the observation that leaves contain considerably more Ca than storage organs or the young enclosed tissues from the same plant (19,23,126). Poor Ca distribution within the plant can also explain both the frequent appearance of Ca-deficiency disorders even on Ca-rich soils and the failure of Ca fertilization..."
Rick
Well-Known Member
Yes noted in more than one source (including the Cornell document). Which may go back to why urea based ferts may see better results than nitrate based ferts with high K.
Rick
Well-Known Member
I don't either, but:
1) no NPKK content is listed so concentration presumed
2) his dilution rate is high
3) his frequency of application is low ("once every month or two")
4) his substrate is inorganic and low retentive so most of what goes in goes right out.
5) uses tap water of unknown hardness (but certainly harder than rain or RO water)
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.
Stone
Well-Known Member
Weakly weekly is a bit unsatifactory as a recommendation. It could mean anything. For instance I would consider 1/2 strength every week way to much. 1/2 strength every month with water in between more acceptable. But I would prefer 1/8 strength every week or maybe 1/16 strength every watering ok as well.
Full strength once per month
1/2 every 2 weeks
1/4 every week
1/8 every 4 days
The plant will see the same amount of nutrient with all of these but there's a big difference in EC fluctuation!
So yes if ''weakly weekly'' means 1/2 strength every week then I agree it is too much in many cases. It also gets complicated when you have to factor in plain water irrigations.
I remember proposing a while back that a very very weak solution given with every watering might be best. Lance (GW) said it wouldn't work.
It is almost getting to the ''old fashioned'' way of giving a little blood and bone once on spring and once in Autumn! It worked with the humusy composts used then but maybe not with the modern bony type mixes.
