North of major structures is the least desirable location and is good only for plants that require little light. Deciduous trees, such as maple and oak, can eff-ectively shade the greenhouse from the intense late afternoon summer sun. Deciduous trees also allow maximum exposure to the winter sun because they shed their leaves in the fall. You should aim to maximize winter sun exposure, particularly if the greenhouse is used all year. Remember that the sun is lower in the southern sky in winter, causing long shadows to be cast by buildings and evergreen trees.
Good drainage is another requirement for the site.
When necessary, build the greenhouse above the surrounding ground, so rainwater and irrigation water will drain away. Access to the greenhouse should be convenient for both people and utilities. A workplace for potting plants and a storage area for supplies should be nearby. The chosen site and personal preference can dictate the choices to be considered. An attached greenhouse can be a half greenhouse, a full-size structure or an extended window structure.