The Culture of Miltoniopsis
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The Miltoniopsis produce among the most beautiful and often fragrant flowers in the Subtribe, Oncidiinae. The cultural requirements of these intermediate growers have long been misunderstood. Because these Hybrid Miltoniopsis are so far removed from the species it is fair to say they possess a great deal of hybrid vigor. They grow quickly into specimen plants with great numbers of spikes and flowers, rewarding the grower with exquisite display plants for show and enjoyment. Cultural requirements well practiced will yield plants that grow and flower year after year with ease.

Temperature and Light

Miltoniopsis prefer temperatures that do not fluctuate a great deal. They do not require a great deal of temperature difference between night and day for flowering, as is the case with other orchids. A night temperature close to 60 degrees. Daytime temperatures 65 to 75 or even 80 are fine. The only difficulties in temperatures are during non-peak growth periods of winter and Summer. In the winter,  plants can be kept drier when the outside temperatures are in the 30s. In Summer more frequent watering is ideal as the plants are in active growth. Light levels should be between 1700 and 2200 foot-candles. When the light levels are correct the leaves will be turgid and upright. When too shaded, growth is limp. Here in the Pacific Northwest we use shading form the first of March to the 2nd week of November, clear glass the remainder of the year. 

Watering and Feeding

Miltoniopsis will require special treatment during non-peak growth periods which are during the winter and Summer. In winter the plants should be kept drier when the outside temperatures are very cold. In the Summer the plants will require more frequent watering. Miltoniopsis should not be kept too dry during  active growth periods, and will respond to dry conditions with accordion pleating on the leaves. Miltoniopsis respond well to fertilizer, as do all living things requiring food. A low phosphate fertilizer is what we recommend. Always water your plants well the day before applying any fertilizer, as the plants should be well hydrated. Fertilize your plants once a week at half the recommended strength. This will be adequate.

Humidity and Air

Humidity is an important factor often overlooked. Miltoniopsis are native to the Andes of South America in cloud forest and need 55% to 65% humidity. More is required when the temperatures are higher. Good fresh air movement is always a benefit to living things. Plants are no exception.

Potting

There are many different potting mix blends. From 50% peat/perlite for fiber pots, to the standard bark mixes for plastic pots. The key here is the dynamics involved in growing in a particular mix and pot. Whatever your choice, plants benefit from repotting. When the medium breaks down, flower size and productivity drops off. Miltoniopsis respond better if underpotted in a smaller pot rather than overpotting in a larger pot.  Potting is done after flowering season from fall to early spring.

Orchid Ailments

Miltoniopsis are relatively free of pests and diseases. Slugs and snails are always the most common problem with any orchid. We do recommend the A.O.S. handbook, "Orchid Pests and Diseases", available from The American Orchid Society.