Orchids are epiphytes, a plant that grows non-parasitically on another plant, such as tree, and gets its moisture and nutrients from the rain, air and the debris around it.
"Most of the orchids we are growing are growing on trees in the tropics," explained Jim Grogan, master gardener and greenhouse technician at Mount Holyoke College. Orchids need to be given conditions that make them feel like they are in their home environment, he said during a recent lecture at Hadley Garden Center.
"Orchids are really easy if you know what to do, but they are not low-maintenance plants. If you want to grow orchids, you have to be committed to attending to them regularly," he said.
Grogan has been caring for almost 500 orchids at Talcott Greenhouse for the last four years. He is also tropical ecologist.
Orchids are the most diverse plant family on the planet, containing more than 30,000 species.
"If you are a tropical orchid [in the rainy season] high in the crown of a tree, you are going to get soaking wet. And then the sun will come out and you're going to dry out," he said. "So orchids want to be soaked, and then they want to dry out. That's really the key to understanding how to treat orchids."*
For orchids, the most important part is the roots. "If you have happy roots on the orchid, you will have a vigorous plant," he said."We don't put orchids in soil ... because the soil will stay wet and roots will rot," he said. Special bark medium mixes are ideal for growing orchids and can be found in plant nurseries.
What makes an orchid unique is that its female and male reproductive parts are fused into a column inside the lip which is highly specialized for insect pollination, said Grogan. The insects takes the pollen away and inserts it into another flower. The flower also has a set of three sepals and three petals. "One petal is almost always modified into a lip," he said. This is what catches our eye, and attracts pollinators, he said.
"I don't grow anything that won't flower," he said. "The flower for me is who the plant is in the end."
Leaves, Stems Contain Clues for Watering
Orchids will usually bloom at the same time every year. "Most of the orchids that people grow in their homes are from seasonal tropical environments where the flowering season is now: January, February and March. So that's why you're going to have so many orchids in flower for shows," Grogan said.
Just looking at an orchid can tell you how to grow it, he said. The orchids Grogan brought with him to his lecture had different leaves and stems which make them adaptable for either dry or moist conditions.
Of the many varieties of orchids grown in the world, here are six of the common species available:
|Phalaenopsis are the most commonly purchased orchids.|
"Most of everything we buy is a hybrid raised by the millions by large factories in Florida, Hawaii and Taiwan," said Grogan. These factory conditions make orchids perform better for consumers. They are usually affordably priced, very hardy and vigorous, he said. Most orchids purchased from big box stores are phalaenopsis orchids planted in sphagnum moss, which aids in shipping long distances.
However, the sphagnum moss is not ideal potting material for these epiphytes. Grogan recommends replanting phalaenopsis orchids into a medium consisting of tree bark, sponge rock and charcoal, which aids in quick drainage for the plant. In addition, the orchids should be repotted into orchid pots, which have slits or holes on the sides of the pots and aid in rapid water drainage. "Take the plant to the kitchen sink and spray the whole plant and roots," he said. Then let the plant dry out. Grogan recommended watering them every four to five days this way.
Usually the leaves of the phalaenopsis are thick and succulent with very few white roots. This orchid is a rainforest plant that grows on trees, on the bases of trees or afixed to trees. Phalaenopsis are low-light plants, and prefer morning light.
Grogan recommends fertilizing weakly (1 tsp to a gallon) every 10 days during the spring to fall; in the winter time, every couple of weeks. He said a 10-10-10 fertilizer is fine to use.
"Move orchids outside during the summertime. They love being outside," he said. "I leave them outside almost until it frosts." To rebloom, the orchid needs cooler night temperatures. The early fall temperature drop in the evenings will initiate flower spikes, he said. After the flower blooms, he recommended cutting off the old spikes so they do not drain resources from the plant.
*Grogan explained that since there are so many orchids in the world, that there are exceptions to growing them. These are the most common ways.