A guide to container gardening

No acreage needed for a sumptuous garden when a simple pot will do

Courtesy of US Arboretum

Who doesn’t love those scorching summer afternoons when a new crop of cherry tomatoes has ripened on the vine? You intend to harvest handfuls, but your basket doesn’t fill up; you’ve popped too many of them into your mouth. You sink your teeth into its sun-warmed, red-ripe skin, and realize it’s no surprise your yield is the envy of the neighborhood. As the juice dribbles down your chin, you begin to appreciate the fruits of your labors.

You have the satisfaction of tossing those fresh-from-the-garden tomatoes, nurtured through spring and early summer, into a salad. Maybe you snip off some leaves of basil to top that pizza for dinner. Or flavor a glass of iced tea with homegrown mint. Nothing beats the freshness of your own fruits and vegetables. Best of all? You don’t have to have an in-ground garden to have a harvest: You just need a pot.

Even beginners can enjoy the success that comes with container gardening. For novices and dedicated gardeners alike, these gardens offer the perfect combination of commitment and experimentation.

They are an alternative for those whose outdoor growing options might be limited to a patio, balcony or other small space. But even if your yard is spacious, containers like hanging baskets or window boxes can create interest. Groupings of pots set on stairs to the front door can be captivating—and useful. They can serve as accents along a driveway, or hide unsightly transformers or faucets.

It’s not just about artful arranging; you can harvest lettuce, herbs or enough cherry tomatoes to make your neighbors’ mouths water. And if they ask nicely, you just might share them.

Think Outside the Box

Container gardening has become more popular over the years, says Scott Aker, horticulturist at the U.S. Arboretum in Washington, D.C. Because parameters can be controlled unlike a garden in the ground, there’s less of a concern about soil-borne diseases and no threat of pesticides. What you will get: intense flavor, vibrant color and the satisfaction of growing and harvesting flowers, herbs or vegetables yourself.

The first thing to note, says Aker, is that in this area there are three distinct growing seasons: spring, summer and fall. The end of one season heralds a new one, providing an opportunity to try out ideas, plant combinations and sample harvests.

It’s important to think about how much time you’re willing to dedicate, says Aker. If the answer is not much, go easy the first time around. The fragrances, textures and colors at the local garden center can be overwhelming. So start small. Give yourself something to work up to.

Start to think about planning a container garden with what are known as cool-season plants, as early as March or April. For example, says Aker, radishes and broccoli, and any of the salad vegetables like lettuce, arugula and kale do well in early spring. But by the time the temperature starts to heat up, those leafy greens need to be pulled from the pot. In their place, transplant six-pack flats of your favorite annuals. Change “them out with peppers, tomatoes and any of the mainstream heat-tolerant plants in early to late June,” Aker says.

And when those late-summer blooms start to look a little tired come September, start planting your next round of cool-season plants, like lettuce, cabbage, onions or ornamentals such as pansies or chrysanthemums.

Aker offers one caveat: Beginners plant “container gardens in the spring, and they think, ‘Oh, I’ve got to keep this going.’ You’re not going to keep a cool-season plant happy through the summer. You’ve got to have a little bit of a ruthless mentality about ripping things out and replacing them.”

How to Get Started

Containers are just as varied as the plants that can grow in them. Anything goes, says Margaret Atwell, a gardener at the U.S. Botanic Garden in Washington, D.C. Choose from terracotta, fiberglass, whiskey barrel, wooden window boxes—the key is to have proper drainage.

But get the basics down first. Even though this area is known for a spate of toasty days in April or May, be patient. Don’t plant warm-season plants like tomatoes, cucumbers, dahlias or cannas until after Mother’s Day.

“A lot of people just throw stuff in, and they think, ‘OK, I’ll just use whatever,’ and then everything’s dried up and dead, and they’re upset, and they just get discouraged,” says Beth Ahern, also a gardener at the Botanic Garden.

To ensure that doesn’t happen, pot placement is crucial. That is, will your plants live in sun or shade?

“We always try to emphasize the right plant for the right place,” says Ahern. “It’s very important that when the public come for classes here that they understand their piece of the garden—or the deck, or the patio—that’s going to be shaded or full sun.”

Atwell recommends homeowners follow the Botanic Garden’s container mantra: Bigger is better.

“Container combination is a lot more interesting if you can get three or more plants in it,” she says. “Your standard terracotta pot is maybe 8, 10 inches across. That basically holds one plant. So you need to think about something that’s at least 18 to 24 inches across the top so that you have the possibility to get three to six plants in there to make something interesting. Otherwise it’s a very dull combination.”

Atwell suggests thinking as professionals do: “You want something that’s a ‘thriller,’ meaning your big, focal point; you want something that’s a ‘spiller,’ meaning something that’s trailing over the side, or hanging down somehow; and you want something that’s a ‘filler,’ which if you were doing a bouquet would be something like baby’s breath,” she says. “You want something that’s mid-height in there, [and] you want a tall element and a low, trailing element.”

How Does Your Garden Grow?

Maintaining proportion in a container garden is important, says Sara Williams, horticulturist and landscape designer at Alexandria-based Campbell & Ferrara. Combine flowering plants; contrast textures; think about impact. But most of all, says Williams, have fun.

A tall plant might be an ornamental grass such as purple fountain grass; a pink geranium could be a filler; a spiller like Vinca or ivy might trail over the edge. Even window boxes of white and purple impatiens, or hanging baskets of fuchsia can be creative combinations.

Nothing says summer like flowers in hot hues: oranges, reds and magentas. Bright-colored Wave petunias, geraniums and begonias are the most popular annuals in this area, says Williams.

Summer plants really thrive here, and the choices of what to plant are infinite, says Atwell. Consider variegated coleus; verdant, trailing sweet potato vine; tall, fragrant lavender; sunny marigolds and multicolored ornamental peppers.

At the peak of those hot and humid days, the harvest of vegetables, herbs and flowers provides a veritable bounty. And when it’s time to swap out the summer blooms, chrysanthemums and pansies do well in their place for fall color and interest.

The Edible Garden

If you like instant gratification, consider herb gardening. Experts say tough love is the best advice for basil, mint, parsley and rosemary. Herbs are easy to maintain, as they thrive in poor soil, full sun and require little to no fertilizer.

It’s a world of difference when you grow your own. The flavor from those lush, green leaves will be more intense than that of the bunch that’s available at a supermarket, says Aker. Plus, at home, you can snip off as much or as little as you want. For the inventive cook, cultivate a rainbow of basils, from purple Thai, to lemon, to traditional. Additionally, says Aker, “there are some herbs like fennel—they do double duty because they are very ornamental with their feathery foliage, but they’re also an herb you can use in cooking.”

Edible gardens are gaining in popularity, says Williams. From tomatoes and peppers to popular herbs like rosemary, thyme, basil, dill and cilantro, people are growing what they cook with most. Just remember, she says, to “make sure you have six hours of sunlight. They need full sun.”

Our hot, humid summers are ideal for growing red and golden cherry tomatoes, or plump multicolored heirlooms.

And in this area, tomatoes and herbs are the gold standard for summer harvests, says Peg Bier, a manager at Merrifield Garden Center. “People like to grow their own, pick their own, harvest their own,” says Bier. “Vegetable gardens are really in. … You don’t have to worry about changing their position or their soil because they’re growing in fresh soil every year. You just have to choose containers that are large enough.”

Children begin to appreciate what goes into what they eat, says Bier, who has taught her own grandchildren about gardening, from seed to table. “The 3-year-old eats the beans and cherry tomatoes right off the plant,” she says.

What could be more satisfying than that?



Q&A With Sandra Reichert

Community horticulture program coordinator, Green Spring Gardens, Alexandria
For Fairfax Country residents interested in gardening outside their homes, consider renting a garden plot at one of nine locations. But be forewarned: There is a waiting list.

When did the program get started, and how many people participate?
There are approximately 700 plots located at nine sites across Fairfax County. The Garden Plot rental program began in the mid-1980s. Approximately 650 citizens participate in the rental program.

How does someone sign up?
There are waitlists maintained for each site. Fairfax County residents can sign up on the waitlist at www.fairfaxcounty.gov/parks/gsgp.

How big are the plots? Can residents rent more than one?
There are two sizes of plots. The majority of plots are 20-by-30 feet, and they rent for $45 per year. There is a site without water service, and those 20-by-30-foot plots rent for $40 per year. At Grist Mill Park, there are a few 10-by-20-foot plots, and those plots rent for $40 per year. Current rules allow one garden plot per household.

Does the county provide any assistance for plants, such as pro­viding soil or water?
Water is provided at eight of the garden plot sites. One site, Eakins Park, does not have water available. Green Spring Gardens offers an array of basic gardening classes throughout the year which are taught by Green Spring Master Gardeners. The gardeners are responsible for fencing, tools, hoses, sprinklers and any other items that are needed for gardening.



Container Gardens for Beginners

1. Choose Your Container. Familiarize yourself with the benefits and disadvantages of each type of pot or alternative container option. Different varieties of containers suit different types of plants. See “Pot Shots” on pg. 98.

2. Select Your Soil Mix. Soils for containers must be well drained, have good aeration and retain enough water to maintain good growth. Miracle-Gro Moisture Control Potting Mix contains a polymer that absorbs and stores up to 33 percent more moisture so you don’t have to water as often. If you prefer a traditional soil mix, a 1:1:1 mix can be made. Mix together one part good garden soil, one part peat moss and one part perlite or coarse builders sand.

3. Start Watering. Check containers daily; the amount of water will vary based on size of container, amount of sunlight and type of plant used. Water thoroughly so entire soil ball is moistened. A good sign is when the water is dripping out of the drainage holes at the base of your container.



Pot Shots

According to Sara Williams, landscape designer and horticulturist at Campbell & Ferrara in Alexandria, there are pluses and minuses to each container option:

Terracotta pots hold warmth and allow your plants roots to breathe. However, if it is cold, soil may freeze and expand, causing your terra cotta containers to break. They are also not the best option for an active household with animals and children.

Glazed clay pots aren’t as porous as terracotta. There are lots of styles and colors to match individual tastes. They can still break in cold weather, and sometimes you may need to drill your own drainage hole. Check for this before buying.

Plastic pots are less costly. They can resemble terracotta containers and can be moved or cleaned more easily than terracotta. However, plastic doesn’t allow your plants to breathe freely. Williams says she uses a lot of fiberglass pots on rooftops; they are very light.

Stone containers can add a natural effect to your house or garden landscape, but are often heavy and hard to move.

Non-traditional containers allow you to get creative. With non-traditional containers, however, you must remember to drill drainage holes into the bottom.

Tips from our Experts
– Don’t plant warm-season plants until Mother’s Day.
– Remember that some plants thrive in full sun; others, in shade.
– Know when your home experiences sun and shade.
– Check plants daily, but don’t take daily care.
– Use a pot that has drainage holes to avoid root rot.

Tips on Watering
– Do not water every day in hot weather.
– Establish a need before watering plants. Be sure that the soil is genuinely dry.
– Stick your finger in the soil. If it feels dry, give it a good drink.
– Water sufficiently until water drains out bottom of the pot.
– If the soil is wet, check it again later. Do not water.



Local Resources


Merrifield Garden
Merrifield Location: 8132 Lee Highway, Merrifield; 703-560-6222
Fair Oaks Location: 12101 Lee Highway, Fairfax; 703-968-9600
Gainesville Location: 6895 Wellington Road, Gainesville; 703-368-1919

Campbell & Ferrara Outdoor Living
6651 Little River Turnpike, Alexandria; 703-354-672

U.S. Botanic Garden
100 Maryland Ave. S.W., Washington, D.C.; 202-225-8333
For classes and events: www.usbg.gov/education/events
Admission to all public areas of the U.S. Botanic Garden is free.
Conservatory Hours: 10 a.m. to 5 p.m. daily, including weekends and holidays

United States National Arboretum
3501 New York Ave., N.E., Washington, D.C.; 202-245-2726
Admission is free.
Hours: The Arboretum grounds are open every day of the year except Dec. 25 from 8 a.m. to 5 p.m.

(May 2010)