Masdevallia, a genus of some 350 species usually from cool, misty
mountains of the New World tropics, is known for its showy flowers with sepals striking in
their size, shape, and/ or color. Their need for a cool, damp environment makes them an
excellent choice for cool, coastal climates.
LIGHT levels for this group usually are thought to be fairly low; however,
some successful growers believe that the best flowerings are produced under higher light
levels. Plants can be grown, but not necessarily flowered, in the same light levels as
those for ferns -- 400 to 1,000 foot-candles. Most growers maintain levels adequate for
Phalaenopsis and Paphiopedilum -- 1000 to 1,500 foot-candles. Masdevallias can be kept in
light intensities up to 2,500 foot-candles if the growing area can be kept cool. Plants
grow well under four- tube fluorescent fixtures and can be summered outside in shade.
TEMPERATURES should be cool to intermediate; plants will grow slowly and
eventually expire if temperatures remain high for long periods of time. Cool evenings help
reduce heat stress during the day. Nights of 50 to 55 degrees F are ideal; day
temperatures should be 60 to 75 degrees F. Evaporative cooling pads or humidifiers are
useful in maintaining these conditions.
WATER is critical for these plants because they have minimal water storage
tissue. Roots should be allowed to become just dry before watering again if drainage is
adequate, constantly moist roots are fine.
HUMIDITY is important for these plants. The ideal range is 60% to 80%. In
the home, mist the plants (in the morning only) and set the plants on trays of gravel,
partially filled with water. In the greenhouse or enclosed growing area, misting or
wetting down the floors can increase humidity, while evaporative coolers help raise
humidity and lower temperatures. If plants are summered outdoors, automatic misters under
the benches are recommended.
FERTILIZER should be applied regularly while plants are actively growing.
Applications of 30-10-10 type formulations twice a month are ideal for plants in a
bark-based medium. A 20-20-20 type formulation should be used for plants in other media.
If weather is dull, applications once a month are sufficient. Some growers use high
phosphorus, 10-30-20 type formulation (bloom booster) as plants approach flowering.
POTTING is best done in the winter or early spring, before the heat of
summer and/or as new roots are produced. Plants must be repotted frequently, every one to
two years, to keep the potting mix from decomposing. A fine-grade potting medium, such as
fine fir bark or treefern fiber, is often used with plastic pots. Sphagnum moss is also
used, especially for establishing plants. The bottom one quarter to one third of the pot
should be filled with drainage material, either broken crock, rocks or Styrofoam
"peanuts." The plant should be positioned in the pot so that the newest growth
is farthest from the edge of the pot, allowing the maximum number of new growths without
crowding the pot. Plants growing in many directions may be positioned in the center of the
pot. Spread the roots over a cone of potting medium and fill in around the roots with
potting medium to the junction of the roots and the plant. Firm the medium around the
roots by applying pressure. Keep humidity high and the potting medium slightly dry until
new roots form. A vitamin B1 compound may help establish newly potted plants.
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