By Staff
Mary Beth Musgrove,
Extension Program Associate,
Horticulture, Auburn University
One of the most versatile and creative forms of gardening is container gardening. Planting a container garden is much like creating a floral arrangement. However, live plants can be enjoyed for a season or longer period of time. Almost any plant can be grown in a container when proper growing conditions are provided and can add a temporary splash of color and art wherever desired.
Choosing a Container
Generally, plants can be grown in anything that will hold soil and allow proper drainage. Some of the more traditionally used containers include terra cotta (clay) pots, plastic pots, hanging baskets, wire baskets lined with sphagnum moss or fibrous liners, concrete planters, planter boxes, whiskey barrels, 5-gallon buckets, tubs, and bushel baskets. Some of these containers are more durable than others are.
Don't limit yourself to the traditional when it comes to choosing a container. Choosing a container that fits the look you are trying to create is half the fun of container gardening. Containers can be window boxes (wooden or plastic), wooden wine crates, tires, bags of potting soil, garbage bags filled with growing medium (called a sausage garden), or your favorite old boot.
Some self-watering containers have been manufactured to improve drainage and also have built-in reservoirs for watering plants.
Planting
Before setting out plants in a container garden, first determine how the plants will fit or be arranged in the container. Always remove plants from the container they have been growing in before planting them in your garden. Cover the drainage hole in the container, using pieces of broken pottery or some mesh screen to prevent the soil mix from clogging the hole. Fill the container about three-fourths full with soil mix. Moisten the soil mixture thoroughly. Allow the mix to settle, and then add more soil mix to again fill the container to about three-fourths full.
Always start with healthy, disease-free, and pest-free seeds and plants. If direct-seeding a container garden, plant seeds at the proper planting depth and season according to the germination and planting recommendations. After the seeds germinate and the plants put out their first true leaves, thin the seedlings to the proper spacing by cutting off extra seedlings. This reduces root disturbance and allows seedlings to grow without competing with each other.
Fertilizing
Some soilless mixes used for container gardening do not contain fertilizers. In this case, you will need to add trace elements that plants would otherwise obtain naturally from garden soil. Slow-release fertilizers that supply all the nutrients needed for a container garden are available. Another reason to use a slow-release fertilizer is that nitrogen is slowly released to plant roots, providing the necessary fertility throughout the growing season without burning plant roots. Fertilizers are salt and when overused can burn or kill plants. Fertilizer salts can build up over time in soil mixes and porous container materials such as terra cotta. Wash porous pots with a 10 percent bleach solution before planting to remove salt buildup.
If additional fertilization is needed, a water-soluble fertilizer (i.e., Miracle Grow, Peters, and others) can be used to supplement initial fertilization. Follow label directions on all fertilizers.
Watering
The most critical and time-consuming part of maintaining container gardens is watering. This is particularly true as plants mature and roots leave very little soil in containers. As a general rule, plants grown in full sun require thorough watering two to three times a week. Mature plants may have to be watered once or twice a day during the hot days of summer.
Remember that porous containers such as terra cotta (clay) dry out more quickly and can wick water away from plants. Avoid growing plants that require full sun in black containers. Also remember that water-holding polymers or gels can be used to retain moisture as needed by plants.
Another way to reduce watering time is to install a drip irrigation system with emitters on an automated timer.
Containers can also be placed on trays filled with gravel or marble pebbles covered in water to help keep them cool and to provide moisture without creating a drainage problem.