Question
Wayne,
I have had a couple of Phals which have started losing their leaves, the leaves are green for the most part, but then have started turning yellow at the stem/"trunk" and has continued turning yellow all the way to the tip.

Because it first rots, turns yellow at the stem/trunk, the leaves sometimes have fallen off given that the leaves are heavy and they simply weigh too much for the rotting part to support.

I am wondering if this is just a natural event where the leaves fall off only to give way to new ones OR if there is something else wrong. I had treated one of them with Fungicide to make sure it was fungus free, but did not seem to matter.

I live in Orlando, Florida and water my plants once per week; sometimes I give it a bit of a mist during the week if it is too hot outside (it is in the upper 90's nowadays) ... I feed it 20-20-20 weekly.

Thanks in advance for your help, as always.

Please advise.
Angelo

Answer
Angelo, you can expect that occassionally an older leaf will yellow and fall off and be replaced by a new leaf. However, it may be, with the high temperatures and humidity, your potting mix is degrading causing some root rot.  You could check this by unpotting one of the plants that has been losing lower leaves to see if you have any mushy or stringy roots. Repot to a fir bark based potting mix. Plants kept above 90 degrees for a prolonged period might show signs of heat stress in this manner so increase shading or air movement or both. The problem with misting is that, while it has a cooling effect, the plants so cooled need to dry off by nightfall.  Unless you have good air movement, the high humidity could retard evaporation of the moisture left on the plant from the misting.  I assume you now have moved the plants out of your garage and found a shady spot to grow them.