Phals like temperatures 75 degrees F and higher during the day and in the mid-60s at night year-round. They start a flower spike when exposed to temperatures in the upper 40s to 50s for a couple of months in the fall when left outdoors. However, you should never expose them to frost.
They are an epiphytic plant, meaning that they grow on other plants. They grow in the bright shade near the top of jungle forests, so bright shade indoors or out is best. Bright shade would be enough to barely see your shadow.
If they are planted in a bark mix, they may need to be watered every five to 10 days depending on the temperature. Don’t let the roots dry out. If they are planted in only sphagnum moss, watering intervals may stretch to 10 to 21 days. Be careful to not overwater. If you want to do the ice cube watering method, poke a few holes in a paper cup and put the ice cubes in the cup.
Fertilize with an orchid fertilizer following label directions. Repot them in the spring if the plant is growing over the sides of the pot. They like humidity in the 50 percent to 70 percent range.
Oncidiums have long sprays of small flowers that last a long time. They grow well in normal home conditions: temperatures in the 70s in the day and in the 60s at night are good. The best situation is 2,000 foot-candles to 3,000 foot-candles of light. Don’t let them dry out in the summer, but reduce watering in the winter.
Cattleya orchids are known for the huge flowers often used for corsages. They need temperatures in the 80s during the day and in the 60s at night, so find the hottest room in the house for them. They need 2,000 foot-candles to 3,000 foot-candles of light. Direct sun will burn the leaves, and they shouldn’t get extra light at night. Water them before they dry out. They have a pseudo bulb that helps them through dry spells, so don’t overwater.
The Paphiopedilum orchids are also known as Lady Slippers. The ones from tropical regions can be grown in continuous temperatures of 70 degrees to 80 degrees, and some of the temperate-region ones need to have low temperatures in the 50s to initiate flower buds. They are forest floor orchids, so they do best in 900 foot-candles to 1,500 foot-candles of light. They need to stay humid with damp soil.
Cymbidiums are perfect for people who have cool homes with temperatures no higher than in the 70s during the day in summer and in the 60s at night. The night temperature needs to drop into the 50s in the fall for flowers to form. They love light up to 8,000 foot-candles. They love water and fertilizer.
A few other orchid genera that you may want to read up on are the Dendrobiums, Miltoniopsis, and Vandas. A couple of good books to read are “Understanding Orchids” by William Cullina and “Orchid Modern” by Marc Hachadourian.
