Last October I was given a beautiful Orchidaceae Dendrobium, which flowered profusely for weeks. When the spike finally finished, I cut it off and watched in delight as another one appeared from the base. It reached about 10cm, then, while I was away for a few days (during which time the weather was extremely cold and the central heating was off at night) the single leaf turned black at the base and collapsed. (I cut it off immediately after taking the photo.) Now what seems to be another spike has started to appear, and I'm anxious it doesn't share the same fate. I can't find any obvious cause apart from the temperature, and when I spoke to a very helpful Baby Bio representative she recommended some intensive tlc. So the dendrobium is being cosseted with a drip-feed bottle of Baby Bio Orchid food, and their new Feed and Mist, which covers the plant in an extremely fine spray. Fingers crossed this does the trick, and I will post an update.