Phal Orchid leaves with patchy green and yellow areas

[sweta]

Originally Posted by Ray

If the water is high in alkalinity - which is not the same as having a pH above 7 - it will eventually shift the rhizosphere pH upward.

As far as pH affecting nutrient availability or the ability of the plant to take it up, that is only true if the pH is toward the extreme ends of the scale. Please read this and this.

Besides, microbes and the plant, itself, affect the pH far more than does the solutions applied. Prove it to yourself by doing a simple pour-through test, described in one of those articles.

Yellowing - assuming it really is a nutrient deficiency - is caused by a lack of nitrogen and magnesium, not calcium. If you simply go to a more appropriate feeding regimen, it ought to resolve it going forward. The affected leaves may not recover.

Thats very interesting Ray. I will try the pH test suggested in the article.

Yellowing - I will go to an appropriate feeding regimen as suggested.

Thank you Ray!