Plants survive by converting carbon dioxide in the atmosphere into oxygen. To ensure the garden always has access to carbon dioxide, we need to make sure the are we choose for our garden has sufficient airflow.
If the garden is located in a large, centralized area of the home you really don’t have to worry about airflow. There should be plenty. If, on the other hand, the garden is located in a closet or in some other out-of-the-way place, improper airflow is a concern.
The easiest way to overcome this is to add a fan. A simple box fan for the local big-box store is sufficient to move air over even large indoor gardening setups. Just be careful not to turn up the fan too high as this will damage many plants. A slow, gentle breeze is all that’s required for optimal airflow.