AOS Catasetum & Relatives Culture Sheet

Catasetum & Relatives

Including Cycnoches and Mormodes

These unusual orchids offer fascinating, often waxy flowers that have the peculiar habit of discharging their pollen masses (pollinia) onto pollinators. Almost always deciduous, the pseudobulbous plants have strict growing and resting periods.

LIGHT should be strong, especially near the end of the growth period. Early in the annual growth cycle, plants will tolerate less light - from 1,500 to 3,000 foot-candles. Plants grow best with light levels of 3,000 to 6,000 foot-candles, or 1/4 to 3/4 full sun. As pseudobulbs mature, harden them by giving slightly more light.

TEMPERATURE. These orchids are native to hot tropical areas and grow during rainy summer months. During this growing period, day temperatures of 80 to 100 degrees F and night temperatures of 60 to 65 degrees F are beneficial. After growths mature, temperatures should be reduced to 55 degrees F at night, with day temperatures of 70 to 85 degrees F.

WATER is critical for producing large pseudobulbs and strong flowerings. Since these plants only grow for a short period, a great quantity of water must be stored by the plant. Water heavily as new leaves are forming. After the pseudobulb is mature, gradually reduce watering frequency. The leaves will yellow and start to fall. At this time watering should be stopped completely until new growth begins again. Water during this dormant period only if the plant shrivels severely; overwatering may cause the pseudobulbs to rot and die.

FERTILIZING is very important for producing strong pseudobulbs. Use a high-nitrogen formulation (30-10-10) while plants are in active growth, slowly tapering off as pseudobulbs form. Bloom booster formulation (10-30-20) should be used in the fall except for plants that normally bloom in the spring.

POTTING is best timed to coincide with the start of new growth (s), usually in the spring. New roots will be produced quickly at that time, and plants will not experience any setback. These plants have vigorous root systems and like to have a rich and moist potting medium during their growing months. Many growers remove the plants from the growing medium during the resting period to ensure dryness during that time. Fine-grade orchid bark is common for smaller pots; medium-grade bark is used only on large plants. Sphagnum moss is used successfully for plants in many areas, as it provides tremendous water- and fertilizer- holding capacities. Some plants may be grown on slabs of treefern or other material, which makes it easier to keep them dry during dormancy; however, it is harder to keep them moist while growing. When well grown, these orchids can be divided down to one mature bulb and then bloom on the next mature growth.

Spider mites are a common pest of these orchids when in leaf; control by keeping humidity high and/or spraying with recommended miticides.

Prepared by: Education Committee, American Orchid Society, 6000 S. Olive Ave., West Palm Beach, FL 33405 (407) 585-8666.