Thank you for the suggestion Ray ; any kind of deficiency/imbalance had not occurred to me. I should say that it is only perhaps 1 in 10 or 1 in 20 plants showing this, and some of them have several growths, only one of which is like this.
However, the fertiliser mix which I am adding to very low EC water ( good rain, or RO water) is one dveloped from the MSU fertiliser as discussed in the AOS mag, - June 2003.. The developed formula is :-
11, 8N + 2,7K2O + 11, 8CaO = 3, 5MgO + 4, 8SO3 plus trace elements.
The N is not urea, and is intended to be fully absorbed. Bark, which is my present basis is fairly rich in Calcium and I think is released as the bark breaks down, if the pH is correct. My fertiliser/water solution usually comes out at about 6.0 pH when the EC is 600µS and if not is corrected to lie in the 5.8-6.3 range , with dilute phosphoric acid or potassium hydroxide as the case may be.
Everything else in the greenhouse is growing well ; but a thought, despite what I have said about humidity; the other benches have been covered with polycarbonate sheets to present a flat surface ( slightly sloping for drainage) and are covered with capillary matting, fed with water by micro-drip jets every few days to keep them fairly damp - and perhaps keep the roots cooler too.
There is no doubt that the cattleya bench is a lot drier ; it always was when I used metal ballast lighting which inevitably provided heat too ; I had thought that switching to LED would be an improvement, but not noticeably so, I find.
I have been toying with the idea of using the cap[illary matting trick on the cattleya bench.
Those other benches grew plants well but with poor flower count until I realised that my enthusiasm for hanging plants over them, meant poor light ; this does not happen with the cattleys which have supplementary lighting . So I added supplementary lighting to the side benches ( sun-blaster strip lighting) and now they too are flowering well.
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Originally Posted by Dorsetman
