Container gardening, whether you choose tubs or pots, allows you to garden with flexibility. You can use a single container to hold different plants of different heights to create a special focal point, and you can reconfigure your garden at will for aesthetic reasons. Planting in containers also lets you control the amount of sunlight each plant gets, because you have the ability to move your planters from one spot to another.
Choose an appropriate container. Containers come in many sizes and colours, as well as many materials -- plastic, terra cotta, glazed ceramic, and wood.
Select a variety of annuals to plant in the type of container you choose. Annuals are better than perennials in cold climates because perennials usually will not survive the winter -- in a container they are not insulated at all from the cold as they would be if they were planted in the ground. In warmer climates, perennials are a good choice because they will bloom year after year, given the proper care.
Diagram how you want to arrange your selections. One possibility is to plant some tall flowers in the middle with smaller flowers and a vining plant, such as vinca, around the perimeter. You can grow almost any flower in a container; lily of the Nile, bird of paradise, daylily, African daisy, begonia, petunia, black-eyed Susan, lantana, zinnia, marigold, pansy and snapdragon are all good, almost foolproof, container gardening choices.
Check your container for drainage holes. Most containers intended specifically for plants do have drainage holes, with the exception of glazed pots. Use a 1/4-inch masonry bit and an electric drill to put drainage holes in glazed ceramic pots.
Place clean pebbles and river rocks in the bottom 1/3 of the container to keep the potting soil from clogging the drain holes when you water the plants.
Fill the container to about 2 inches below the top with soil that is suited to the flowers you want to plant. Most flowers are fine with the normal potting soil that is available at garden stores and home-improvements stores. You can add 1 cup of compost for every gallon of potting soil to add more nutrients. Or you can mix up your own potting soil using equal parts peat moss, perlite, compost and garden soil. Arrange the plants in each container and put them in the soil, tamping them down firmly to avoid leaving air spaces in the soil.
Water your container plants frequently. Remember, these plants cannot draw moisture from the ground and dry out much more quickly. Water the containers thoroughly when the soil feels dry. Water coming out of the drainage holes indicates the plants have received enough water.
Fertilise with a slow-release plant food for flowers, following the manufacturer's instructions for the amount and frequency of applications, Just as the flowers in a container cannot absorb water from the ground, neither can they absorb nutrients.
Paint wood containers with one to two coats of sealer before you plant in them.