Odontoglossum and Miltonia Care

[fred]

(Cold tolerant genera)
These high altitude orchids are popular where cool temperatures prevail. The 'pansy orchid', or Colombian Miltonia, (truly Miltoniopsis) and showy Odontoglossums, have striking sprays of flowers. Culture is similar for hybrids in this group, some being Odontonia, Odontioda, and Vuylstekara.
Temperature is critical for these plants; day temperatures below 75 to 80 degrees F are preferred year round. Night temperatures of 55 to 58 degrees are best. Short periods of warmer day tempertures may be tolerated, especially if humidiy and air movement are ideal, and nights are cool. Miltonias prefer night temperatures at the upper end of the range, while many Odontoglossums thrive at 50 to 55 degrees at night.

Light levels should be bright, with some sun allowable. An east window in the home is ideal, or shaded south. West is usually too warm in most climates. In a greenhouse, levels up to Cattleya strength (2000-5000) footcandles) are acceptable; some Miltonia growers demand the pink flushing in the plants' leaves which results from the high light levels. If summer day temperatures are hot, light levels can be reduced to cool the growing area

Water should be plentiful, coupled with perfect drainage. The potting medium should just start to dry before watering again. "Accordian" pleating on Miltonia leaves is a symptom of insufficient water or humidity, and may appear on other genera if severe. This may mean watering every two to seven days, depending on weather, pot size and type, and type of potting material.

Humidity is important for all these orchids, coupled with moving air; 40% to 80% being ideal. In the home, set the plants on moist pebbles, without the pot setting in water. Misting is beneficial, but in the morning only. Evaporative cooling in a greenhouse increases humidity while cooling the air, and is highly recommended for these orchids in most climates. Fogging the air, or damping the floor with water also helps cool and humidify

Fertilizer should be applied regularly while plants are actively growing. Twice a month applications of 30-10-10 type formulations are ideal for plants in a bark-based potting medium. A 20-20-20 type formulation should be used on other media, or on slabs. If weather is dull, once a month applications are sufficient. Some growers use a high phosphorus 10-30-20 type formulation "bloom booster" as plants approach flowering.

Potting is best done as new growth begins from the base of the plant, which is usually in the spring or fall. These orchids like to be very pot bound, so when repotting, leave only enough room for one to two years new pseudobulbs. A fine potting medium with excellent drainage is required; since the medium is kept moist, annual or biannual repotting is normal. Usually one-quarter to one-third of the bottom of the pot is drainage material, either broken crock shards, rocks, or styrofoam "peanuts". Spread the roots over a cone of potting medium and fill in around the potting medium well around the roots by applying pressure. Keep humidity high, and the pot drier, until new roots form. A vitamin B-1 compound may help establish newly potted plants.

Miltonias will sometimes send up two sets of growth a year, and bloom from each growth, sometimes with two flower spikes per pseuodobulb.

[ann]

when you talk about 10-20-30- etc what do you mean in regards to fertilization