Choosing the right container for a plant is very important. A plant should have just enough room to grow to its full size without having confined roots that can restrict its growth. Additionally, a plant that is placed in a pot that is too small can run out of water too quickly. At the same time, a plant that has too much room can retain moisture in the pot as if it were planted in a garden sponge. Plants that do not like "wet feet" can develop root rot.
Choose a container that is one to two sizes larger than the plant that you are planting. This provides enough space for the plant's roots to develop.
Select metal or dark-colored containers three sizes larger than the plant you are planting so that you can line them with waterproof insulation to protect plants inside from extreme temperature fluctuations.
Select large diameter containers for arrangements with multiple plants in them
Consider the size of the plant's roots when selecting a container. Tomatoes have deep roots, and need containers that are at least 12-inches deep, while radishes only need containers that are 4-inches deep. Plants with roots that grow 6 inches into the ground or less need a small containers. Plants that grow deeper than 8 inches need a large container.
Select small containers for bulbs so that they can be moved for chilling periods. Large, concrete containers are ideal for perennials, trees or shrubs because they offer more protection to the root system.