Where Food Grows on Walls and Windowsills

Some apartment-dwellers are greening up their living space by growing some of their own food indoors. The most determined have found it possible to grow a salad’s worth of kale, microgreens, tomatoes and peppers along windowsills and light-filled walls.

Making it easier are vertical planters, hydroponic systems and dedicated grow lights that run on timers. “Everybody is getting a little bit more ambitious about what it is that they want to grow,” says Britta Riley, founder of Windowfarms, a maker of vertical, self-watering hydroponic garden systems based in Brooklyn, N.Y. Ms. Riley started the company in 2011 after she set out to create an indoor vegetable garden in her own fifth-floor apartment and found she had to build one from scratch. Prices for the system, which can hang from a windowsill or sit on a shelf, start at $199.

Figuring out what grows best takes experimentation. It’s easiest to stick to smaller-size vegetables like cherry tomatoes and jalapenos. Kale, Swiss chard, spinach and some lettuce varietals often do well in apartments. Peas and basil thrive in a warm environment with moderate sun, but strawberries, cherry tomatoes and peppers require full, warm sun. Vine plants also require a structure to grow onto as they climb.

Veggies that don’t require deep soil, such as radishes, can work. Even citrus fruits like lemons can grow inside. Some root vegetables, including beets or potatoes, call for large amounts of soil and are best avoided.

Many indoor gardeners rely on hydroponics, growing plants without soil using nutrient solution and water. Unless they live in a greenhouse, many indoor gardeners decide to adopt some form of artificial lighting.

For most vegetables, even a sunny windowsill requires extra light, says Nate Storey, co-founder of Laramie, Wyo.-based Bright Agrotech, which sells hydroponic towers for both indoor and outdoor use. Some lighting systems rotate automatically to provide direct light to more plants. Light-emitting diode lamps are a good bet because they use little electricity and don’t generate heat.

Some companies have started marketing LED and low-heat fluorescent lighting systems that were originally developed for indoor marijuana cultivation. “The larger market opportunity is folks growing lettuce in their kitchen,” Mr. Storey says.

Towers are a space-efficient way for consumers to garden and maximize sunlight. An added benefit is that the vertical orientation lets water drain more easily.

Vertical herb planters now come in appealing finishes with upscale materials like copper and chalkboard. “It’s almost as if you’re hanging a piece of art,” says Allison O’Connor, vice president of merchandising at Williams-Sonoma Inc., which plans to double the amount of indoor gardening merchandise offered in its agrarian section by September. A vertical planter with a copper finish has 10 planting cells to accommodate herbs and costs $189.

At IKEA, the Socker mini-greenhouse, a $19.99 glass box with a vented top useful for sprouting seeds or growing other small container plants, is especially popular with apartment dwellers, says Janice Simonsen, IKEA’s design spokeswoman.

IKEA has expanded its indoor gardening inventory after introducing an indoor seed kit four years ago and is developing a line of pots and plant stands meant for small urban spaces, she says.

Growing her own greens has helped get her 2- and 4-year-olds interested in vegetables. She likes gardening in a design-conscious way. “Using recycled bottles just looks terrible,” she says.

Start by claiming the best-lit windowsill space, or an area in the home with plenty of artificial light. Mint, parsley and sprouts can survive without full sun on a kitchen island. Most vegetables need plenty of light—more than can be provided by a standard-size window.