| Both your plants would prefer cooler temperatures around 25 days but they will handle the higher temperatures. Mine get up to 32-40 C (90-105F)
The pebble tray of water will both increase humidity and cool the temperature around the plants. You might want to find a heavier shaded area. I find certain areas around my house near my pool are 2-3C degrees cooler in the summer.
The heat will definitely dehydrate the plant faster. When they are actively growing they can take more water. It is not possible without seeing the plants to recommend a change in watering, but as a general rule - actively growing plants in the heat of summer use more water than fall-winter when they hibernate.
Since your plants are flowering they are certainly healthy. An increase in water will help. It is possible that the lower leaves will die. This can be normal growth pattern for a Phal. Plants will often drop older leaves especially if they were young leaves. Any Phal leaf under 4-5 inches usually dies in a year as larger leaves take its place.
Lower leaves are also hidden from the sun. Without being necessary to produce food (which they can not do if hidden from the sun) the plant will discard the leaves to conserve water in your heat.
Sounds like a normal growth pattern.
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jerry  |