They helped break ground for the plot on the South Lawn last month.
Spinach, salad greens, herbs and berries are among the crops planted.
The fifth-graders from Bancroft Elementary tend to a similar garden at school. They will return to the White House for the harvest and to help cook some of the produce in the White House kitchen.
Some of the crops also will be served at the White House and donated to a local soup kitchen.
The Obamas began discussing such a garden since they moved to the White House in January, Mrs. Obama said.
When asked about the week's first pooch rumors, she only said the Obama girls would have a dog "soon."