The children paused at the entrance to the greenhouse, bunched together and hesitant to move forward. In front of them, on the tables and hanging from the ceiling, were dozens of plants with names they could barely pronounce.

"I want you to look around," prodded Joyce Harris, a volunteer teacher, as she walked around the glass building hoping to challenge at least one of the eight kindergartners to take the first step. "Use your eyes. Where is the tallest plant? Is it this one?"

"No. It's this one," exclaimed 6-year-old Shaun Wood as he broke away from the group and proudly pointed to a two-foot-tall zinnia plant.

And just like that the antsy bunch became a throng of curious budding green thumbs, all wandering off on their own to explore the plant-filled oasis. There were plants with babies (spider plant), plants with leaves that feel like wool (rudbeckia) and plants with flowers you can eat (nasturtium).

Welcome to the greenhouse at Langley School in McLean, one of only a few left in the Washington area and perhaps the only one maintained by an elementary school. Here, students from nursery school to eighth grade help grow plants and vegetables that eventually are sold at school fund-raising events or donated to neighbors.

In an age when schools are stressing technology and spending more money to buy computers, Langley's insistence on maintaining a greenhouse seems to be a throwback to the days when there were more farms than office buildings.

"It goes back to children not being exposed enough to the natural world," said Harris, a parent of a Langley student who has been volunteering as a horticulture teacher. Instead of sitting in front of the computer, "Langley's greenhouse allows students to get their hands dirty, to experiment and explore something that is living."

Betty Brown, head of the private school, said that Langley always had a horticultural program but that the addition of the greenhouse 12 years ago has helped strengthen the curriculum. The 18-by-31-foot gabled glass building was donated by the daughter of radio personality Arthur Godfrey.

"Langley students learn from an early age how to understand, preserve and protect nature," Brown said. "Experiencing and appreciating nature is well integrated into our program of studies."

At most schools, classroom trailers and tennis courts have replaced many of the greenhouses, which were often the first to be cut during a budget crisis. It's not clear how many schools in Fairfax County had greenhouses, but school officials said they are aware of three high schools that still have them, Annandale, Fairfax and Thomas Jefferson.

Of the handful of school-operated greenhouses in the Washington area, virtually all of them are at high schools or vocational schools. For instance, students at Leesburg's Charles S. Monroe Vocational Technical Center maintain one of the largest greenhouses in the area.

At Langley, about 350 students immerse themselves in greenhouse projects that include simple tasks from growing beans in a clear plastic cup to a six-week experiment to determine which elements affect plant growth.

In the past year, school officials estimate, more than 2,500 plants were grown in the greenhouse. Some were sold at a spring fair to raise money for the school, others were donated. Last month, students planted three dozen pansies grown in the greenhouse in front of the American Legion building in McLean.

But more important, the greenhouse has provided a unique opportunity for learning about horticulture firsthand.

Recently, about 45 students in Diane Hren's eighth-grade science class broke into three teams in a competition to see which group could grow the tallest zinnia plant.

After days of doing research on the Internet and reading books of plant growing tips, Andrew Levy's group used special nitrogen-rich fertilizer to grow the winning plant.

Meanwhile Mark Hopke's team tried various types of compost, which didn't fare as well. They even tried placing multivitamin tablets in the soil, which were a little more effective, Hopke said.

"We knew that humans need the nutrients so we wanted to see if plants needed the same nutrients as well," Hopke said.

Nisha Chadha, whose team tried injecting glucose into the soil but eventually settled on the plant food Miracle-Gro, said the experiment taught her to appreciate how fragile nature could be. The plants with glucose eventually got infested by red ants attracted to sugar.

"We had to water the plants during lunch breaks and keep an eye on them all the time," she said. "It was a lot of work."

Last week, their younger kindergartner counterparts were being initiated into the world of horticulture, getting their first tips on potting a plant.

"You don't want to press it down," Harris said, as she showed the students how to fill the pot with soil. "You know why?"

"Because it'll go through the hole," Lisa Herbert, 6, said confidently, as she lifted the plastic pot to reveal holes in the bottom of the pot.

"No. You want air in the soil," Harris said.

CAPTION: This planting schedule helps the class keep track of what is growing in the school's greenhouse.

CAPTION: Lisa Herbert, 6, holds a cup of soil for planting flower seeds. Next she'll learn what makes them grow.