Most Phalaenopsis orchids will bloom for quite a long time, some up to six months on one inflorescence. Depending upon their ancestry some will put out side shoots from their main inflorescence (blooming stem) and continue on blooming. As long as the inflorescence is green you have a chance to keep it blooming. Cut back the stem to the third or fourth spot where a bloom was attached (called a node). These nodes are apparent on the stem by a triangular marking on the bloom stalk. If you want to grow and re-bloom the plant, you will need to cut off even blooming inflorescences in June or July or some plants will simply bloom themselves to death and never rebloom.
If the inflorescence is turning yellow, then the plant has finished blooming and the stalk should be cut back close to the bottom of the plant. Put a little cinnamon powder on the cut to keep from getting rot there. Then let the plant grow naturally to store up enough energy to bloom again.
As the temperatures start to moderate in the fall your orchid will need about a month of cool evening temperatures in order to set a new inflorescence. Most hobby growers simply put them outside during the night for that period, or open a window in the growing area so that cooler temperatures can encourage the plant. The ideal temperature will be in the 55 degree Fahrenheit, or 13 degree Centigrade, area. Continue with these cool nights until you see an upward growing all green growth. It somewhat resembles a root growth but the color is different and you can make out a slightly rounded area at the growing tip rather than the pointed tip of a root.
Once the inflorescence has started you can stop the cool night treatments since the plant will continue to grow the flower stalk. As the inflorescence grows to about 6 inches, or 15 centimeters high, stake it to control the inflorescence. Be very careful of keeping the plant facing the same direction in relationship to the sun or the flowers will be poorly spaced on the stem. A good suggestion is to move the name tag to the side of the pot facing the sun so that when you move the plant for watering you can simply put that side back toward the light source. As the flower buds grow try to keep the humidity up around the plant. Many home growers have lost flowers due to low humidity -- this is called “bud blast.” The buds simply dry up and fall off.
Then sit back and enjoy your beautiful flowers for three or four months! Phals are one of the most enjoyable orchids because they reward you for so long with their lovely flowers.