Question
Dear sir,
I have recently purchased some 30 phalaenopsis plants from a dealer of Anthura, Neitherland in India. At the time of purchase almost all had 5 leaves, I planted them in a mixture of wood charcoal and tree bark compost. At first some leaves turned yellow and eventually damaged. Now new leaves have started to grow along the new roots with in a month of potting. But till now I find leaves turning yellow in some plants, my pots are free draining. Our climate is very hot and humid, temp has now gone upto 36/37 C, its expected to go upto 48/50 C. My plants are kept under a roof in a balcony ambient light is available only afternoon mild sun reaches the plants. I water the plants in the morning and then mist with a sprayer 1 or 2 more times daily.
What other precautions shall I take?

Answer
I suspect that the plants are being grown too bright.  If possible, expose them to only early morning sun and shade them more heavily the rest of the day.  If you have access to shade cloth, use 40 percent or build a small lathe house.  At those temperatures, you need to provide constant air movement to cool the leaves.  If the plants are sheltered from natural breezes or if there is little natural air movement, use one or more fans for cooling.  If you use fans, you may be able to mist more heavily to cool them and the fans will help to dry out the plants before nightfall.