Backyard Greenhouses Are Growing on Homeowners

Her second iteration, the Cottage Model by BC Greenhouse Builders, was erected this past February. It is 192 square feet and 12-feet high and cost roughly $20,000. That cost included extras, like additional ventilation, double storefront doors, pressure caps and hardware, but didn’t include the installation and the concrete foundation.

“I learned so much about what worked and didn’t work with my first greenhouse,” says Ms. Yewchuk, “that when it came to designing the second, I knew exactly what to change.”

Historically, elaborate, ornate greenhouses were fabricated for high-society households while more utilitarian versions were operated by commercial agriculturists. Today, home gardeners and plant aficionados alike are building and maintaining them in their own backyards. According to Angela Drake of BC Greenhouse Builders, the Surrey, British Columbia-based manufacturer and supplier of Ms. Yewchuk’s greenhouse, the company’s website traffic increased over the past year by 177%. More than 75% of that growth was driven by U.S. customers, she says. Maintaining the structures is easy, but ”what is challenging is the learning curve of growing and maintaining the temperature, humidity and sun exposure. It is a science experiment and will take a full year to understand the changing seasons,” says Ms. Drake.

“When the garden goes dormant in the winter, the greenhouse comes alive,” says garden connoisseur and decorator Bunny Williams, whose Falls Village, Conn., property hosts a 25-foot by 50-foot, metal-framed greenhouse purchased 25 years ago from W.H. Milikowski (now Griffin Greenhouse Supplies) for under $10,000. Ms. Williams’s three-bedroom home is surrounded by a studio, converted barn and conservatory, and multiple gardens all situated on 22 acres of land she’s accumulated over 30 years. “It’s more of a commercial greenhouse that I’ve tried to make as attractive as possible,” she says about the greenhouse’s wood borders and trim. “It functions beautifully.”

It is the challenge of procuring and growing exotic varieties that keeps these enthusiasts hooked year round. For Ms. Williams, who is in her 70s and maintains an interior-design practice and home in Manhattan with her husband, John Rosselli, who is in his 80s, the greenhouse became a place of solace during the pandemic as she dug, clipped and propagated her plants.

More recently, it has become a showplace for all the rare specimens she tended to during lockdown, including auriculas, one of her favorites. Ms. Williams acknowledges that her horticultural habit is a luxury. “I don’t buy expensive art or jewelry. I’ve become a plant collector,” she says. The collection includes orchids, succulents, passion flowers and geraniums. “I always say, a house is one thing, you can dust it once a week and it’s fine, but anything living requires daily care.”

Horticulturist Deborah Munson, 63, is head gardener at Twin Maples, a pastoral property in Salisbury, Conn., built by Douglas Thomas and her late husband Wilmer Thomas in 1996.

With views of the Litchfield Hills, Twin Maples incorporates a 40-acre wildflower meadow, with grounds based on a formal footprint and a Georgian-style house, designed by the late decorator David Easton. Encircled by both a reflecting and a swimming pool, terraces and formal gardens, the custom greenhouse is anchored by flower and vegetable gardens.

Mrs. Thomas and Mr. Easton chose handmade brick from North Carolina for the walled gardens to match the exterior of the main house. A metal pergola marking the entrance to the greenhouse was produced by Battle Hill Forge, in Millerton, N.Y. By September, the structure will be enveloped in sweet autumn clematis, fragrant and in full bloom.

Somewhat taller than a conventional estate greenhouse, Mrs. Thomas’s 1,040-square-foot version was built by Frank Jonkman and Sons Ltd. (now JGS Ltd.) with Agritechnove Inc., consulting engineers who assisted with the automation and computer system that controls and regulates heating, ventilation, shading, irrigation and misting systems. Separate warm and cool zones as well as a potting shed and exterior cold frames, a protected box structure in which roots grow and seeds germinate, were also incorporated. A weather station positioned on the roof monitors wind speed, direction, temperature and humidity as well as ambient light levels.

When the pandemic hit, interior designer Thomas O’Brien and his husband, designer Dan Fink, hunkered down in their Long Island home in Bellport, N.Y. In 2015, the couple built a walled garden and greenhouse there. The garden wall is made of Glen-Gery brick, which cost $25,000. The customized 114-square-foot Straight Eave Greenhouse by BC Greenhouse Builders cost $8,700.

“My greenhouse is not big. But I wanted to make it special. It’s incredibly useful,” Mr. O’Brien says about the traditional lean-to with cross-country frame, which is essentially a backyard model painted in a chic shade of dark green.

“I wanted it to feel vintage and classic,” he says. The greenhouse details include an antique black slate sink discovered in Bar Harbor, Maine, and a custom wood-panel door, also painted green. A mix of roses, palms, figs, peonies, sunflowers and herbs sourced from Peconic River Herb Farm in Calverton, N.Y., are just a few of Mr. O’Brien’s favorite plants.

“Because we were home all winter, I was able to be there daily throughout the season,” Mr. O’Brien says.

Kathryn Herman, a 57-year-old landscape designer, built a greenhouse on her property in Fairfield, Conn., in 2016, at a cost of around $324,000. “Greenhouses have a different smell, temperature, light and humidity than that of being outside. When you step into one, you are in a totally different environment, which makes them magical,” says Ms. Herman.

The customized greenhouse sits near the garage at the back of a 6-acre property, which she and her husband, Ron Herman, 58, purchased in 1998 for $950,000. The main house is 4,000 square feet with four bedrooms and 5½ bathrooms while an additional 2,000-square-foot guesthouse was also created for friends and family.

Ms. Herman’s 500-square-foot metal-framed Alitex greenhouse is equipped with Wi-Fi, warm and cool sections, and a heating system with sensors that monitor the temperature and never allow it to rise above 80 degrees.

“It’s all about ventilation,” says Ms. Herman. The greenhouse automatically opens and shuts the roof vent. Meanwhile, the motorized sensors gauge the climate best suited to her plants. “Air circulation is so important, so plants don’t become diseased,” Ms. Herman says. Positioned on an east-west axis, the length of the building gets southern exposure, while the built-in cold frames also get maximum sun.

“Since I’ve added it, the greenhouse is the place I spend most of my time. Even in summer,” Ms. Herman says.