Sudden changes are much harder on plants than gradual changes. When moving plants during the winter, it is essential that they be properly wrapped and protected. Sudden exposure to low temperatures often causes leaf drop and drooping. Make sure this warmth is maintained during the night too. Higher humidity is needed when propagating plants at warmer temperatures.
Some plants react to cold temperatures by developing dark, almost black leaves that curl.
Others will fail to bloom as they should or the leaves will look limp. Plants that are kept too warm tend to grow too quickly and develop weak growth. Excessive heat can also interfere with blooming resulting in less blooms or weak blooms that don't last very long. It can also result in wilting even though the plant is adequately watered. These symptoms can also be the result of too little light.