Garden plants Can Thrive in Containers
posted on February 22, 2005 11:41am
Contact: Leslie Johnson or Mary McLellan
517-432-1555 or 355-5191
EAST LANSING, Mich.—OK, so a collection of flower pots, window boxes and bags of potting soil full of thriving flowers and vegetables isn’t the return of the hanging gardens of Babylon. But it can be the solution when the problem is nowhere to garden.
“Container gardening isn’t new, but plant breeders keep introducing new varieties of vegetables, especially, that were designed specifically for container gardening,” points out Mary McLellan, Extension Master Gardener program coordinator at Michigan State University. These so-called ‘bush’ or ‘patio’ varieties of crops such as cucumbers and tomatoes give good yields in small spaces.”
Other plants are just naturally suited to growing in small spaces. Leaf lettuce, radishes and other salad vegetables; onions; individual pepper, eggplant, tomato, broccoli and cabbage plants; carrots; zucchini; and greens such as spinach and Swiss chard generally do well in containers on a sunny apartment balcony or patio.
If vertical space is available, try vining crops such as pole beans and climbing ornamental plants such as morning glories and sweet peas, she suggests. Just be sure to anchor the poles or trellis securely so it doesn’t blow over.
Other candidates for a container garden include a variety of herbs and a host of flowering annuals and tender bulbs such as tuberous begonias and caladium.
Almost any container can be adapted for gardening, McLellan points out. Clay pots and window boxes are just the beginning. Plastic or metal pails, old washtubs, wooden boxes, bushel baskets—even the bag that your favorite soilless planting mix comes in can hold plants.
“The container needs to be big enough to hold what you want to plant in it, sturdy enough to last through the growing season and heavy enough to resist being blown over by the wind,” McLellan sums up. “It also needs drainage holes in the bottom to let excess water escape. Otherwise, rainy periods will leave the soil saturated and plant roots will rot.”
During dry weather, the soil in containers will dry out quickly—more quickly than the soil in a conventional garden—so it’s a good idea to check containers daily and water whenever the top inch of soil is dry.
The growing medium in a container garden isn’t garden soil, of course. Garden soil contains disease organisms, weed seeds and harmful insects, and if it’s high in clay, it will drain poorly when it’s wet and harden to a bricklike consistency if it dries. A packaged, sterile potting mix provides a good combination of moisture-holding capacity and air spaces for good root growth. It’s also free of disease organisms, weeds and soil insects, though these can blow, walk or fly in later, or be introduced on plants.
What plants you can grow in your container garden depends largely on how much light your garden spot has to offer. Full sun—defined as at least six hours of direct sun per day—means you can grow plants that bear fruits, such as tomatoes and peppers, and sun-loving annuals such as petunias, geraniums and marigolds. In a lightly shaded area or a spot that gets morning sun (an eastern or northern exposure), ornamentals such as coleus and tuberous begonia will thrive, and leafy vegetables such as lettuce and spinach will do just fine.
Sometimes too much sun can be as big a problem as not enough, McLellan notes.
“Even sun-loving plants may get too much sun in an unshaded western or southern exposure, especially if incoming sun is reflected back on them by a nearby light-colored wall or other surface,” she points out. “If your garden site gets the full benefit of the late afternoon sun, choose plants that thrive in hot, dry environments and be prepared to give them extra water or shade them.”
Container-grown plants also need regular fertilizer for good growth. A water-soluble fertilizer applied according to manufacturer’s directions is probably the easiest way to provide plant nutrients.
Because the soil in containers is quicker to warm up than the soil in a conventional garden plot, plants tend to grow rapidly and may begin to produce sooner, if sun, water and fertility are adequate, McLellan notes. Container growers may even be able to get a head start on the gardening season by placing containers in sunny, sheltered locations days or even weeks before general outdoor conditions are conducive to planting.