Help, Phal leaves...disintegrating???
 

I noticed one leaf last week, but now it's 2 leaves on one phal, and now happening to another phal. Something very strange with the leaves. These orchids are in my terrarium.

Slug? Medium looks too wet.

I just watered the plant, thats why. I have not seen a slug anywhere in the terrarium, nor any bug.

Check the area at night since that's when slugs make their appearance.

You definitely have slugs or snails. They hide in the medium.

Caffeine kills them. Brew strong coffee and let it cool (high octane, not decaf.) Water the plants thoroughly with plain water so the roots are very wet, and they won't take up the coffee. Now pick up the pot, cover the drain hole with your finger and pour coffee in to the brim. Hold it for 30 seconds and let drain. If there are too many holes to cover with your finger set it in a container and put the pot in for its to-the-brim bath.

I'm agree. My first thought was slugs or snails. Use the coffee route.

Never heard of the coffee trick, thanks.

I've done the coffee thing and it worked for me...and my plant.

Should the medium be flushed clean with water later or should it be left the way it is ?

After the coffee treatment I wouldn't flush. Start with wet medium so the roots take up as little coffee as possible.