For a variety of reasons, people sometimes prefer to grow their plants in a pot (or at least start them out in pots).  Whether you are waiting until the plant is more mature before you place it in your garden or if you have a decorative pot that you are wanting to fill, there are a couple of things that you might want to keep in mind. 

Growing plants in a pot is different then growing them in the ground.  Plants are more susceptible to the elements when they are in a container.  If your potted material is outdoors, it can be subject to a wider range of temperatures.  For example, if it is 20 degrees outside the ground temperature might still be 50 degrees.  In a pot, since there is less insulation, the soil has a harder time maintaining a consistent temperature.  The same is true when it is hot outside.  A smaller container can heat up a lot faster then the actual ground temperature.  Drastic temperature changes can cause harmful stress to the plant and its root system.  Using a larger pot, or one with more insulation can help this issue.  The placement of the pot can also help prevent some of the temperature issues.  Keeping your pot out of a lot of direct sunlight when it is warm can help keep the plant cooler in the summer.  Placing your potted material in an area with less wind can help when the temperatures are colder.

If you are planning on keeping potted materials indoors to start and plant outside later, remember that they will still need sunlight and water.  Another thing to keep in mind is that some plants are meant to go dormant when winter comes.  Keeping plants in a controlled environment to prevent this could cause stress that can be fatal to you plant.  Since there are more factors that come into play with container gardening, your potted material might need more care then items planted in the ground.  Keeping these things in mind will help you to be more successful with your potted plants.