Moth orchid (Phalaenopsis) flowers last a long time before they dry up and drop off the stalk. When the last bloom falls, cut back the stalk to the spot just below where the first flower appeared. The orchid may send up a new flower stalk, or it may remain vegetative until next year's flowering cycle begins. Keep your orchid in a bright spot away from direct sunlight. Water the plant about once a week. During times of active growth, when the plant is producing new leaves, fertilize once a month using a full-strength houseplant fertilizer solution. During the rest of the year, fertilize every 4-6 weeks using a half-strength solution.