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Nov 01, 2024

Gardening under glass: Greenhouses a growing idea for homeowners

The notion of a greenhouse conjures up visions of everything from something barely larger than a terrarium to an expansive conservatory, like one found in the gardens of Biltmore Estate. Home

The notion of a greenhouse conjures up visions of everything from something barely larger than a terrarium to an expansive conservatory, like one found in the gardens of Biltmore Estate. Home gardeners usually gravitate to something in between, where seeds can start during the last gasp of winter or that tree nurtured from an avocado pit can survive the cold.

Kelly Toadvine, a master gardener and a past president of the Greater Greenville Master Gardeners Association, now has her own greenhouse. She says home gardeners can choose their own level of adventure. Kits are available online and at stores like Costco, or greenhouses can be “full out” with heat, irrigation and automation.

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“Mine is a greenhouse,” Toadvine says. “It is not a hot house, meaning mine does not have heat built in. Last year, I had to put heaters in to keep things from freezing in there.”

Before adding the space, Toadvine says it is a good idea to think about the purpose of your greenhouse. How will you use the space? To put plants “to bed” for the winter, will the plants go dormant in a cool, but protected, space, or will they need heat to survive?

“I have a greenhouse because I'm a master gardener, so I have an addiction already to plants, and I had so many collections of things that I didn't want to die,” Toadvine says. “I kept asking for a greenhouse, and I got mine because the house was too full in the wintertime. You couldn't sit at my kitchen table because I had so many plants in the kitchen. You couldn't take a bath in my bathtub because that was covered with orchids.”

Vegetable gardeners may find that a small greenhouse is exactly what they need to save money and get the plants they want by starting from seed.

“A lot of times they have a greenhouse, and they don't use it until starting in March or so, and that's when they'll start planting seeds,” Toadvine says. “They'll have to have electric in there to keep things a little warm.”

Some homeowners associations require permission to add a greenhouse and a building permit might be needed, which was the case for Toadvine’s addition.

Before you build, consider ventilation, heating or fans and irrigation.

“I would say any greenhouse that you buy, even if it's just a baby kit, is going to need to have some kind of ventilation, because heat collects and it rises to the top,” Toadvine says. “You have to get rid of it because the plants can't take it. Everything else then becomes an add on – having irrigation in there, having fans in there, having heat in there.”

Toadvine says she initially only thought of the cost of the structure, but each bit of infrastructure increases that bottom line. Maintenance and repair – Toadvine thinks about the possibility of a hail storm versus all that glass – should be considered too.

Toadvine started with a small structure and she recommends that, especially for gardeners who want to save plants like geraniums or ferns.

“You can start small, and then as your passion develops, then people go bigger, and then there's people who just work with what they've got – ‘I can do so many plants in here, and this is all I'm going to do,’” Toadvine says.

But if plants are your passion, consider that in your planning as well.

“If you are a gardener at heart, go bigger than you initially think that you want,” Toadvine says. “I have met a couple of people who are already on their second round of greenhouse because the first one they built wasn't big enough. You can go too big, obviously, but if you're a gardener, when you get the knack for it or the feel for how your specific greenhouse works, you'll find you need more room.”

Even as a master gardener, Toadvine says much of her time in greenhouses was spent shopping. Having her own space presented a chance to expand her knowledge. She faced tadpoles, arctic cold and a lot of the trial and error.

“There is a learning curve to owning a greenhouse – any greenhouse,” she says. “I'm hoping I’ve learned enough from last year.”

For More: visit Greater Greenville Master Gardeners at ggmga.org/