Tolumnia-What is happening?
 

:hello
I.m beginner to grow orchids. I bought Tolumnia and Dendrobium 10 days ago.
Tolumnia was filled with coconut husk. i watered it only twice in these days. The leaves started withering. then i found that the husk getting decomposed. so Removed it slowly and filled it with charcoal. Now i'm sprinkling water daily morning. and it becomes dry by night. I have hanged the pot in the window grill. Even then bottom of the leaves becoming brown and leaves withering. what is actually happening with my Tolumnia?

Tolumnia must dry out between watering. If it stays moist at all it rots, but as a small plant with fine roots and no pseudobulbs it needs frequent water and high humidity, can be hard to find the balance. It naturally grows on twigs, very exposed, dries fast.

:welcomeflowers:

Make sure the media dries out completely before watering. If the media is taking more than 2-3 days to dry, I'd repot it in such a way that it will dry faster. I like to use bamboo skewers to monitor the moistness of potting media http://www.orchidboard.com/community...ine-water.html

Welcome to Orchid Board. So sorry it had to start this way, but everybody will try to help.

What is your climate like now?

It's actually winter here... But the temperature is between 22-30'c

The plant is rotting from staying wet too long.

It should dry Hard in between waterings... It might be best to let it remain dry for several days between waterings. Using the Charcoal instead of Coconut should help.

For this plant which has already started rotting, I would cut off all of the leaves that are damaged/rotted. Do not water the plant much, until it has started recovering (new growth and/or new roots)...

Make sure the plant has some air flow, to also help prevent rot.

Also I have recently bought some orchids here in India, and the plants seemed to be in coconut husk, but I noticed that there was sphagnum in the middle .
I suggest you use a skewer to understand when to water.

I water my Tolumnia nearly (should be not nearly...but I fail sometimes) every day, however, it's in a south window, my humidity is about 50% (low), and it has no media in it's clay pot. It is opening (today) it's first wave of blooms that are completely mine (bought it in April, it was in bloom, it has commenced and matured new growths since then...and spiked again).
I wish you luck with yours, they're amazing little plants.

Actually they filled it up with coconut husk. I changed it to charcoal. Left the roots to expose well. i watered it in every morning only after i see the root dry. Still the leaves are falling. the leaves near the root seem to be shrink-ed and brown. a leaf is yellow. is this the sign of dry or rotting?

It's a sign of lack of water, which is often because the roots are rotted and disfunctional. Tolumnias really aren't geared (imo) to grow in media...but as with most things orchid, it can be done with careful attention to detail.