| A combination of two things will do this. My dendrobiums did the exact same thing when I put them outside for the summer. SUN and the FLOWER COLOR (red/pink/purple colors tend to do this with lots of light). I've seen the same thing on other types too - in some cases you need to carefully watch and make certain they don't get too red - the next phase is BURN. I'm told that once they turn red they will not turn back to plain green too - have yet to prove this - but it certainly appears to be correct. Good luck. mike |