After some decline in the winter, ghost orchids put out at least two new roots when the weather got warmer. One grew to 3/8 inch. I've had them 10 months now. I grow them on my windowsill with Aerangis and Angrcms. Humidity usually stays above 50% and goes up at night as temperature drops. I'm trying to treat them like the other mounted orchids (no extra effort) and am happy they haven't died. Ruler shows that the largest one is only about 1-1/2 inches in size. They are on the original mount from the vendor.
Dendrophylax lindenii by
Gardentheater, on Flickr