KANSAS CITY, Mo. (AP) - When David Bird was 16, his parents took him on a trip to Hawaii. The teenager became fascinated with the exotic flowers that grew on the island - specifically orchids.

Before the vacation was over, Bird had bought five orchids to bring back to the family's farm in Jamestown, N.D., where they grew and sold pumpkins, zucchinis and other produce.

"I was hooked after that," he said.

Today, Bird operates Bird's Botanicals, a tropical nursery in a multi-chambered cave at the Interstate Underground Storage Building in Kansas City. The lighting, humidity and temperature in the cave are carefully controlled to create an environment that nurtures the more than 6,300 orchids and other tropical plants growing there.

The orchids range from white to yellow to pink to dark purple and are solid or variegated in color.

"Every orchid is different," he said.

Bird studied horticulture at North Dakota State University and soon became the caretaker of the university's neglected orchid collection. When he left college, he took one of the orchids with him. That orchid is among the plants thriving in the underground cave. Orchids, if properly tended, can live for generations.

"They have plants that date back to the 1800s in Europe," he said.

After college, Bird worked as a horticulturist at a number of botanical gardens before moving to the Kansas City area about six years ago to take a job with Powell Gardens, a 915-acre botanical garden that features native plants and contemporary architecture.

"I brought 800 orchid plants here," he said. "I built a greenhouse at my home (for them)."

The greenhouse quickly became too small for Bird's growing orchid collection. One day, Bird drove past the underground storage complex and wondered if the caves could be adapted to grow his flowers. He called the owner and set up an appointment.

"I brought a plant and said, 'I want to grow this in your cave,"' he said. "To buy land and build another greenhouse would be expensive. This just seemed like the best alternative."

Bird, who left Powell Gardens five years ago to start his business, said he installed electricity, tables, a watering system using garden hoses and fans in the cave, which has a growing space of about 5,000 square feet.

Overhead lights are the cave's only heat source.

"It took six months for the rocks to warm up," he said.

An environment of 80 percent to 85 percent humidity and at least 70 degrees is maintained in most of the cave.

The blooming room, where plants with buds are kept until the flowers unfold, is kept at 65 percent to 85 humidity. In the summer, the humidity rate might climb to 100 percent.

Hoses hooked up to a hot water heater allows Bird to deliver a warm water-fertilizer mix to the plants each day.

"These orchids are spoiled," he said.

Bird said it's a myth that orchids are difficult to grow. Other than regulating the temperature, humidity and air flow of the space where they are being grown, the plants only need to be watered and fed once a week.

"You can give them good humidity by putting them in the kitchen or bathroom, or misting them or putting them on a pebble tray," he said.

Because orchids are "air plants" and don't require soil, Bird grows his plants in moss or a fir bark mix. Most are grown from seeds.

"It takes seven to nine years for them to go from seed to flower," he said, adding that's one reason the exotic plants are expensive.

Orchids will set enough buds to bloom continuously for two to three months. A pea-size bud will bloom in about four weeks; a grape-size bud will open in about two weeks.

An orchid can produce up to 15 or more flowers per spike. If the spike is cut back while a few blooms are still on it, Bird said, the plant will grow another spike and rebloom.

Bird sells his orchids to florists and nurseries in the Kansas City area. He also participates in a number of lawn and garden shows in the Midwest. In mid-February, he will bring his orchids to the Kansas Garden Show at the Kansas Expocentre.

He also travels to shows in Wichita; Omaha, Neb., and St. Louis and Springfield, both in Missouri. In the summer, he can be found at the City Market in Kansas City, Mo.