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Growing Orchids
The National Capital Orchid Society

GROWING ORCHIDS

Vandaceous Culture

Cattleya    Cymbidium    Dendrobium   Oncidieae    
Paphiopedilum    Phalaenopsis    Vandaceous

These vandaceous plants have a monopodial growth habit. They are strap-leaved plants having flat, leathery leaves.

Temperature - Vandaceous orchids grow best under warm daytime conditions of 65F. or higher but can withstand long spells of hot weather and short spells of cold. They will continue in active growth anytime of the year if given warm temperatures and bright light. Night temperatures generally should be 60F. or higher but not lower than 55F.

Humidity and Ventilation - In a greenhouse, under summer sun, vigorous air movement from a fan is important to keep leaf temperature down. It is important to restrict air movement under colder temperatures. On hot, sunny days, at least 60% humidity is appropriate.

Light - The ascocenda orchid can take full morning sun but needs shade during the hottest part of the day and during most of the day in summer. Under greenhouse conditions with high humidity, maximum sunlight should be given with only enough shade to keep the temperature within the appropriate range.

Watering and Feeding - High daytime humidity is essential, especially on sunny days, and vandaceous plants outdoors may need watering and misting several times daily during the growing season when the sun is bright. Indoors, somewhat less watering is required, but misting once or twice a day in bright weather will be helpful. Water sparingly in winter, during long cloudy spells, or after repotting. Vandaceous orchids are heavy feeders. Plants in greenhouses should be given a solution of Peters balanced fertilizer (20-20-20) once a week during the growing season. Outdoor plants require a heavier concentration of the same fertilizer. During the non-growing season, apply the same proportions every two weeks rather than weekly. In addition at every third feeding substitute Peter's 10-30-20 (Blossom Booster). This is a feeding program for all year long.

Pests - Vandaceous plants seem to have a problem with thrip. These are very small sucking insects about 1 mm in size. Thrip damage usually occurs on the flowers and buds, causing the blooms to lose their beauty rapidly. When thrip is a problem, a spraying program must be adhered to as the plants come into bud. Once the thrips get inside the flower bud, they are somewhat protected from contact sprays. A fine spray mist should be used to avoid injuring the tender buds. Spray young spikes and buds with a solution of Sevin 50W (carbaryl insecticide) wettable powder, following manufacturer's directions. Scale is another pest, use insecticides like Malathion or X-clude. Remember that all these products are intended to kill and should be used in the open air outside your home with caution. A light horticultural oil, like Year Round, (not a dormant oil) which smothers bugs and their eggs is very effective against most pests and fairly safe. Insecticidal Soap is also effective against Scale and is reasonably safe, but it has less residual action. With any of these products some insects, and especially their eggs, will survive to breed again. One dose of even a systemic insecticide will not wipe out a large population of insects totally and completely. Remember to always use any of these products with caution and in accordance with the manufacturers label.