Well Heck! You know if it's complex I'm gonna take a back seat. Thanks for not trying to explain it to me... ya know, that whole Bill Nye thing. :rofl:

Makes sense.

Not necessarily... plants vary in their sensitivity to water quality. Since the Vanda isn't in a bark medium (I think its roots are free in the vase, right?) a good flushing might help keep problem water below the threshold of pain.

Ok, so I've been following up on your ideas/suggestions/requests today.

I had to be at home for a delivery today so I didn't get to the Water Board, that's on tomorrow's agenda.

I examined the underneath of all the leaves of all 6 phals with a magnifying glass. Each plant had at least 2 of it's good leaves with a lot of sticky dew drops around the under edges. Apart from a dead house fly the only other thing I saw was corresponding damage to the upper surface damage on the ones that look distorted.

But! when I examined the top surfaces of the leaves, right where they appear to wrap around the stem, on 2 plants I found a little critter. One was black, one white. I couldn't see them at all without the magnifying glass. I thought at first they were tiny snippets of hair, long and thin (relatively speaking) with the long being perhaps 1.5mm. I tried to capture them using the corner of a damp tissue but before I got near they scarpered into the crevice of leaf/stem. So 2 plants, 2 critters, same behaviour, different colours - any ideas/thoughts?

Fertiliser: I soak my plants in the solution approximately once a fortnight (as per guidelines on the product) but only at a quarter strength solution. Each plant gets it's own solution, I don't share. This bottle is nearly finished and I am about to start a different make, all I could find.

Current product:
https://i.imgur.com/SOiRedb.jpg

Near future product:
https://i.imgur.com/oXqnf8f.jpg
https://i.imgur.com/IBE5V0k.jpg?1
This one says apply every 4 weeks in Summer, 8 weeks in Winter.


Other products I have purchased but not yet used:
https://i.imgur.com/sOrRULZ.jpg?1
https://i.imgur.com/fMV89p6.jpg

https://i.imgur.com/eVjxJdo.jpg
https://i.imgur.com/gztYYBJ.jpg
The active ingredient in this is Cipermetrina.

It's such a shame because each orchid has got a lovely set of roots, such as these:
https://i.imgur.com/n58Zq7W.jpg
https://i.imgur.com/2F1Cpx6.jpg

I'll try my best to carry out your suggestions, answer your queries, least I can do in return for your expertise and experience.:water

Well, I think you may have a diagnosis... those drops of honeydew on the undersides of the leaves sure sounds like a spidermite infestation. They are really tiny, but their effect is big and nasty - they suck the life out of leaves,. I'm afraid I'll have to leave it to others to read the labels...my knowledge of Spanish is, sadly, miniscule. But here are a few ideas to evaluate the various products. First, you need to use something that is listed as a miticide - insecticides won't work, mites are related to spiders (8 legs) not insects (6 legs) For a start, you can kill, or at least slow down, the adults with a good bath of soapy water, even better if it includes some horticultural oil - this clogs the pores of both mites and insects and basically drowns them. However, it only harms the ones that it hits, and doesn't touch eggs or larvae. So a good spraying of that soapy water/oil mix is only a start to clean things up a bit, then follow up with a miticide (the label should specify that it kills mites). Wait a week, repeat. Another week and repeat again (and maybe more beyond that) Treat everything - the orchids, and any house plants in the area, these things spread like crazy. And the repetition is vital, you have to nail each successive generation until there aren't enough survivors to reproduce.

Once you knock down the infestation, if roots are good the plants will probably recover (that one with the dead crown will need to produce a basal growth, but the others will just grow new leaves) So there is hope!

Thanks Roberta, worrying, but something I can get to work on.
When you say give the soapy water treatment, do I take the orchids out of their pots and bark to do this or do I let it all just run down through the bark?
Horticultural oil - I use a diluted oil in the garden as an insecticide/pesticide. I asked the guy in the Agri shop for Neem oil and he sold me this stuff that he said was Neem under a brand name. Is that the type of thing you're suggesting? I'll dig out the container in the morning and have a close look at the composition.

Do these things get right down in the bark?

If they have got in my other house plants, might they have got right down in the soil? Monsteras & Stephanotis
mainly, but pretty large specimens.

Could they be in my bag of bark? Would it be best to ditch it and buy some fresh?

Off to bed now, not sure I'm going to sleep though for worrying about my poor phals :(

Personally, I'd stick with that first fertilizer, at 5-5-5, and apply it at 1 ml/L once a week.

I think concentrate on the leaves - so you can leave them in their pots. Neem in its various formulations is good stuff.

If in the soil, Ray is better equipped than I am to specify how to approach. These teensy nasties are around in the environment. So I think treat as you find them. He also will have some good suggestions.

Don't get too excitable yet FuerteRav. Most stuff with orchids isn't critical manana. Yes, your roots from the one you picture seem healthy. Get the water report, if you can.

Listen to Ray on the fertilizer. Do as Roberta suggests on the Neem oil, etc.

Above all.... Sleep well.

Thanks so much everyone. I'll update on any progress.

I'm still waiting on the Water Board to provide me with an analysis but we had no water supply at all on most of the island for 4 days last week so I think they have been busy dealing with that. The island government have just given a vote of no confidence in the current administration of the Water Board and are supposedly going to implement their own measures to improve and regulate our water supply. Fingers crossed!

In the meantime a friend who has a 'posh' water testing kit for his pool (as opposed to my colour changing dip sticks) came over today and checked my tap water for pH which is 6.4 and Calcium which is 25ppm. I've no idea if these are good, bad or indifferent! Advice needed please.

My Neem container had leaked and was empty :(, the Agri shop hadn't got any more, I've ordered some through Amazon which will take about 2 - 4 weeks to arrive. Plants all drenched with soapy water in the meantime.