Tomatoes and carrots can thrive on a rooftop or fire escape just as well as they would in a backyard. And in addition to the benefits of being aesthetically pleasing and offering easy pickings for a fresh salad, a green roof will act as insulation to keep a home warmer in the winter, and absorb sunlight to keep it cooler in the summer.
If you've never been much of a gardener before, fear not, says Justin Hancock, senior garden editor at Better Homes and Gardens magazine. You'll be surprised how simple it is to sprout corn or cabbage.
"Gardening has gotten a bum rap, mostly because people make it seem harder than they need to," Hancock said. "Either that or people think about having to help their grandparents weed the garden and deal with the bugs, the heat and the dirt. But if you're doing this on a rooftop or a balcony, it's not hard at all."
An urban garden can be as sophisticated as a botanical oasis or as simple as a large planter box with a few favorite herbs.
"I would say most vegetables can be grown with general ease," Hancock added. "As long as they get the amount of moisture and light that they need, most will do pretty well for you."
What you'll need
— The bigger the container, the better. Wide-rimmed plastic or terra-cotta pots with drainage holes are great if you have limited space, but raised beds and large planter boxes are best. They can be watered less frequently, are less awkward to move around, and won't be pushed over by strong winds.
Your raised bed should be at least 8 inches deep and no wider than 5 feet, so that you can tend your garden without having to step into the soil. Building your own is relatively easy using lumber boards that are 6 inches wide and 2 inches thick, stacked one on top of the other. Attach the boards to corner posts using galvanized deck screws.
— Soil. Any garden center will sell healthy loam or bagged topsoil for less than $30 a cubic yard. An added layer of organic material will protect your soil bed and help retain moisture. Commercial mulch can be expensive, but it's easy to make out of lawn clippings, leaves or tree bark.
— Water. If you have access to a spigot, consider a drip irrigation kit, which is affordable and easy to install.
— Tools. Because the dirt is going to be less than a foot deep, you won't need a long garden hoe or shovel. Still, there are basic tools to use to make gardening less strenuous: A hand-held garden fork, or digging fork, is perfect for breaking up soil. Use an ergonomic garden hand trowel to move small amounts of dirt, and snippers for cutting and light pruning. Any of those tools should be easy to find at a garden center for less than $15.
Remember to disinfect your tools with water and bleach to avoid spreading plant fungus or disease.
— Seedlings. Starting seeds indoors or using transplanted seedlings is a good way to get a head-start. Depending on the plant, seeds and seedlings generally sell for less than a few dollars at a gardening center.
What to plant
Remember the general rule of gardening: Right plant, right place, right time. The environment has to be appropriate. For instance, tomatoes can't survive any type of frost, while lettuce, spinach and other greens like the shade.
Most of the vegetables we eat are shallow-rooted and can grow in compact spaces. Herbs, green onions, radishes, squash, cucumbers, peppers, carrots, and spinach won't care how many stories high they are.
Weaving in some small perennials or ornamental grass will help bring your garden's diverse botany together. They require little water or care, and they continue to grow and give your bed a healthy glow in the winter.
Carol Pollard, a staff gardener in the horticulture department for the Brooklyn Botanic Garden who has a hand in its rooftop gardening program, offers these tips for small flowering plants with short roots:
— Prairie dropseed, or Sporobolus heterolepsis
— Purple lovegrass, or Eragrostis spectabilis
— Little bluestem, or Schizachyrium scoparium
— October skies, or Aster oblongifolius
— Angelina, or Sedum rupestre
— Little lemon, or Solidago
What to do
— Fill your container with soil. The soil bed should be at least 8 inches deep.
— Plant your seeds. If you're new to gardening, it's easier, faster and just as effective to start your germination process indoors in smaller containers, or use transplanted seedlings bought at a gardening center. Move your plants outdoors once the danger of frost has passed.
No two plants are alike, so check the back of the package to help you decide what temperatures are best.
If you're confident enough to start the germination process outside, be sure to scatter the seeds so that your garden doesn't become too crowded. Water is usually only necessary every couple of days, and the soil should never stay soaked.
— Don't let your seedlings get too tall or leggy. Using your thumb and forefinger to pinch off leaves at the tip of the main stalk to make your plant stockier.
— Rooftops can wear with time so keep an eye on how level your garden is and disperse dirt where necessary.
— Most vegetables are fussy in cold temperatures. In fall, as frost is setting in, it's a good idea to cut plants down at their base near the soil level. If you're in an area with freezing temperatures, move plastic or terra-cotta pots to a warm or covered area if possible so they don't crack.
To read more about gardening, see the Monitor's main gardening page and our lively gardening blog, Diggin' It. Both of these have changed URLs, so we hope you'll bookmark them and return. Want to be notified when there's something new in our gardening section? Sign up for our RSS feed.