Your guess may well be correct. The plants may also resent the change from
previous to present light and humidity. Many symptoms are common to both
over and underwatering, too much or too little light with over fertilizing
fertilizing or high salt levels. In other words, the answer isn't usually
easy without seeing the plant. With most new plants, I immediately or soon
after purchase, repot to see what condition the roots are in. I then repot
according to the root condition and my general watering regimen. Many people
want to know exactly what proportions of each mix component to use for each
specimen they have. While the orchids may have definate preferences for
certain water and humidity levels, these can be obtained in different ways
according to your humidity levels and watering habits. In your case, I'd
reduce the light levels a little but don't ignore the root condition is it
determines the health of the whole plant. Orchids can tolerate a wide range
of conditions if they are generally healthy.

"Lil" wrote in message
om...
Just picked up a couple of orchids at Costco. Had the orchids in a
warm area with lots of morning and noon sun through lace curtains.

Noticed that the tips of leaves are turning yellow brown--the same
kind of look that burnt leaves have. The flowers are also getting dry
and brown and are falling off.

What is causing the problem? (I suspect humidity is too low or
underwatering.) What can I do to fix it?

Thanks in advance.

Lil