How to build a thriving indoor garden

As you enter the Conservatory of Flowers in San Francisco, there’s a sign that politely requests you shut the door behind you. That’s because the botanical garden’s humidity and temperature are carefully regulated so the plants inside can thrive.

Even if you lack the climate controls of a professional conservatory, you have some power over the conditions inside your home. Want to turn your bedroom into a tropical rainforest? You won't be able to grow a corpse plant bloom taller than the average human, but you can imitate the lushness of a botanical garden by stealing some of their techniques for your personal plant shelf.

This requires some planning. At my local nursery, a group of colorful bromeliads sits next to the succulents. If a customer bought one of each, then put them on the same shelf—or even in the same room—both might be in jeopardy. Although these two types of houseplants are fairly easy to take care of, they thrive in vastly different habitats.

There are many species of bromeliad, including the delicious pineapple, and many flourish in America's tropics. One popular species, Aechmea fasciata, is native to Brazil and grows in areas with an average humidity of 83 percent and 45 inches of annual rainfall. At the Conservatory of Flowers, bromeliads grow in several areas of the garden, each with a slightly different habitat. Some, for example, live in the cloud forest room with orchids and ferns. There, pumps periodically release mist and the mild temperatures match what the bromeliads would experience in a natural cloud forest, 3,000 feet above sea level.

I didn't see succulents inside the conservatory, but there are many outside the building in Golden Gate Park, presumably because they do so well in the mild San Francisco weather. Indoors, these plants generally need as much light as possible and may even need a boost from a grow light. A well-loved indoor succulent with many unique varieties, Haworthia cooperi, is native to relatively dry parts of South Africa, where there's an average of about nine hours of sun a day and 18 inches of rain every year.

So, even if you work hard to control the temperature of your houseplant habitat, properly utilize humidifiers and LED lights, and water your green friends regularly, plants that need vastly different living conditions are not going to thrive together. If a Haworthia is placed near a humidifier meant for an Aechmea, for example, the succulent might burst.

Many of the world’s most-popular houseplants hail from the forest floor, where there’s plenty of water but relatively little sunlight. The plants that grow there generally have large, luxurious leaves to help them capture more of that limited light. Such broad foliage can look great in our homes—unless there’s a shortage of water or humidity and the leaves turn brown.

Air plants are famous for thriving without soil, which makes them a popular decorative item. But it’s important to remember that these plants are, in fact, alive. Tillandsia air plants cling to tree branches and other surfaces throughout their native range, which stretches from the southeastern United States to Argentina. They may not need a lot of soil, but they do need light and water.

Many homeowners tend to gravitate toward houseplants that differ from their native fauna, according to Erin Marino, director of marketing at plant retailer The Sill. She noticed this phenomenon after the company opened its first West Coast location.

“The plants that are super popular in our New York locations are succulents and cacti,” she said. “You go out to Los Angeles, everyone who was coming in was more interested in our leafy tropicals.”

So, a New Yorker who wants to turn their apartment into a desert oasis may want to consider investing in grow lights during the winter and a dehumidifier in the summer.

American bogs are underappreciated. While swamps may be associated with ogres and White House corruption, they’re actually crucial carbon sinks, since they store large amounts of partially decomposed organic matter. They are also home to many species of endangered plants, including the last 125 viable wild Venus flytrap populations.

Fortunately, these carnivorous plants grow and reproduce easily in captivity, so your conscience shouldn’t stop you from buying one from a reputable nursery. If you do, you’ll need to recreate a wetland environment.

These and most other carnivorous plants should be constantly steeped in distilled water or rainwater, which will evaporate and create a high-humidity environment. Pair those bug-eaters with other plants that love moisture, such as the large-leafed arrowhead plant Syngonium podophyllum.

But don’t feel constrained by these recommendations. Some plant shelves, especially those that are exposed to slightly different amounts of light, might do best with a combination of these suggestions. With the right setup you could successfully maintain a lush rainforest canopy above a thriving forest floor. By doing some research on the plants you want and the environment they need before you step into the nursery, you can ensure they shine.