chong

Wow! 7.6 pH water supply. Have you actually tested it, just for accuracy sake? That could be contributing your yellowing leaves. Although, I've read in certain areas, that citrus can tolerate pH as high as 7.0, so I'm not sure that that's a factor here. But coupled with exposure to cold temperatures and winds, it would at least make it suspect. From what I've read, the ideal range is pH of 5.0 to 7.0, with the optimum at 6.0 to 6.5, as you stated.

I mentioned my Philippine Magnolias do not grow very well,even compared to Michelia. Your protocol of testing the soil pH led me to think about checking their pH requirements because the Magnolias and Michelias belong to the same family (In fact, the International Magnolia Society recently renamed the Michelia as Magnolia in spite of the distinct growth and blooming characteristics.) I was puzzled why, despite the same treatment, in terms of temperature, lighting, fertilizing, and watering, the Michelias are more vigorous growing and more productive, but the Magnolias are slow and barely bloom. They both came from the same region in China.

I had misplaced my pH meter from a long time ago and now in a hunt for a good pH meter. Most of the garden shops here only carry an inexpensive one made by LusterLeaf "Rapitest". Do any of y'all have one of these, and are they reasonably good? Thanks for any feedback.