Psychosis Mendon Hall: This orchid has wide thick leaves that have a slight purple and green mottling. The butterfly-like flowers are large and can be 5 to 6 inches in size. The spikes are from 2 to 3 feet in height and can produce flowers many times throughout the year for several years on the same spike. This plant is easy to grow and flower if you follow the guidelines.
Light: This plant requires light similar to Phalaenopsis but can be grown in somewhat shadier conditions at about 1800-3000 foot candles. If your plant has large leaves and fails to bloom, moving it to more light will probably initiate flower spikes. . An Eastern window exposure is recommended or can be successfully cultivated under either fluorescent lights.
Water: When the moss or bark mix just dries out. When in spike or flower water as the mix approaches dryness but do not allow the mix to become completely dry between watering. Overwatering can cause several problems such as root rot and infectious bacteria/fungus in the potting medium..
Fertilizer: Fertilize every other watering in the summer and every third watering in the winter. Be sure to flush the mix with clear water only once per month to prevent fertilizer salt build up.
Repotting: They prefer a well-drained mix with a lot of air. Clay pots are good for larger plants. Change the mix only as it breaks down; approximately every two years. The best time for repotting these plants is in the spring months or when new growth is beginning to appear, as this is when the new roots will break at the same time. Potting mixes can include New Zealand sphagnum moss (with clay pots) or a medium grade bark mix.
Temperature: Recommended ideal night temperature (fall, winter, and spring months) is 60°-64° Fahrenheit and ideal daytime temperature is 90°F. They prefer high humidity, as much as 85% but will tolerate 50% humidity. The use of humidity trays or humidifier may be beneficial. They also require good air movement.