BALLY, Pa. — Three hundred miles may seem like a long way to go for lettuce, but Tuesday’s trip to Butter Valley Harvest Farm was well worth the extra gas for Henry Wilde.

The Pittsburgh farmer is relatively new to hydroponics, and Butter Valley was offering some veteran tips during a teaching session organized by the Pennsylvania Association for Sustainable Agriculture and Penn State Extension.

“I’ve been running my own (hydroponics) farm since August, and I’ve never been to a working farm, so I’m working through every learning curve as it comes up,” said Wilde, who farms butterhead lettuce. “I wanted to come here and talk to someone who’s been doing it for 10 years.”

Seeing Ryan Ehst’s hydroponic operation was an eye-opening experience.

“He’s got all these channels right up next to one another because he’s got these small crops,” Wilde said. “And that surprises me because I could be growing a lot more stuff in the same number of square feet.”

Wilde was one of about 20 people in attendance at the session. And while he may have traveled the farthest, his reason for attending was similar to everyone else’s: curiosity.

Chelsea Mackie is in a farmer apprenticeship program at Pennypack Farm in Horsham and had never seen a hydroponic farm. She was surprised that the growing environment was less controlled than she thought it would be.

“It sounds like you still deal with a lot of the same issues you would if you were growing in the field,” she said. “It’s probably easier in some ways and harder in others.”

Changing perceptions and expanding knowledge was a main goals of the event for Ehst, who led the group on a tour of his Butter Valley greenhouses. The growing facilities consist of four 22-by-128 foot bays, three of which are connected and used for growing herbs and greens, and the fourth for growing tomatoes and cucumbers.

Ehst grew up on the farm, which traces its roots back to a land grant from Pennsylvania founder William Penn.

Looking for a way to expand operations, he and his father, who had just retired from teaching, formed a partnership, drew up a business plan, and went forward with hydroponics.

They broke ground in 2008 and started growing a year later, but didn’t reach capacity until well into 2010, “because you can’t just plant your greenhouse full and get rid of it, unless you want to give stuff away.”

They originally planned for three tomato houses, but realized pretty quickly that was too risky, so they scaled back and expanded into greens.

“The business plan we wrote was for three bays of tomatoes, and we would have never made it,” he said. “Tomatoes are a lot of risk/reward scenario. After the first risky year, we said that’s enough, and got into more greens.”

In their third year they added a fourth house and reconfigured the original greenhouses to better accommodate growing greens.

Along the way, they added a geothermal heating system that allowed the farm to heat the greenhouse with a sustainable source: the earth itself.

The only time the farm uses its propane heaters is when the outside temperature dips into the 20s.

The farm’s main crops are cherry and beefsteak tomatoes, cucumbers, basil, butterhead lettuce, salad blend lettuce, arugula and watercress. To a smaller degree, they grow baby kale, baby bok choy, romaine lettuce and spinach.

Ehst started out selling to a few area chefs and grocery stores, and has been adding customers ever since. His largest buyer now is Lafayette College in Easton, which features his produce in its dining halls. Ehst also manages an on-farm market.

The process of growing hydroponically is pretty simple, he explained. Instead of growing in soil, the plants grow in water that has been supplemented with nutrients.

The system Ehst uses for his greens is a closed system, where the nutrient-rich water is circulated by a pump. But for his tomatoes and cucumbers, it’s an open system where gravity controls the flow of the nutrients.

Ehst uses rock wool to start tomatoes from seed in January. Once the seedlings are established, they are transferred into a system of interconnected buckets, two plants per bucket, and set in the greenhouse.

There are 360 buckets growing 720 tomato vines suspended by spools of string, which will be moved throughout the greenhouses as the vines grow, letting the plants climb up to 50 feet by the end of the season, from March to October.

“The hope is that each plant gets a minimum of 30 to 35 pounds (of fruit). If everything goes well, it should be over 40,” Ehst said.

The air in the tomato house was thick and warm and had the smell of a backyard garden in August. The plants were already towering nearly 6 feet high, heavy with blossoms and fruit. Big fans kept the air circulating.

But there was another, smaller buzzing sound in the air too: bumblebees.

The farm brings in hives of bees to do the pollination work throughout the growing season.

The biggest challenges the farm faces in the greenhouses are downy mildew on the basil and powdery mildew on the lettuces. Ehst says it’s easier for him to prevent these problems than it is to get rid of them once they appear on his crops. Diligent, methodical surveying of his plants is necessary, as is inspection of their nutrient delivery system, where algae will occasionally start to grow and cause the system to clog.

By the end of the tour, the finer points of farming in water started to soak in, giving Wilde a lot to think about on his long journey back to the Steel City.

What impressed him most was the geothermal system that heats the greenhouses.

“He doesn’t use any propane until it gets to 28 degrees,” Wilde said. “My gas bill in January was $5,500. You have to grow a lot of lettuce to overcome $5,500 gas bills.”