Freestanding greenhouses stand alone in the landscape. They can be constructed in a wider range of styles, can be larger, and offer greater flexibility in location than attached greenhouses. These greenhouses can be placed almost anywhere in the landscape where the ground is level and adequate light is available. The most widely used styles are the gable roof, gothic arch, Quonset, and slant-side.

Attached greenhouses can be designed to blend with the architecture and landscape of the home and are useful where space is limited. An attached greenhouse may also cost less per square foot to build than a freestanding greenhouse. With an inside entrance, you can maintain the greenhouse without going outside during bad weather. Utilities such as electricity, water, and heat can be shared with the home if a greenhouse is planned for during home construction. If the greenhouse is attached later, you may need an additional heater because greenhouses lose heat five to ten times faster than an equivalent area of home. The cost of heating an attached greenhouse may be less than that of heating a freestanding greenhouse of the same floor area because one wall is not exposed; however, attached greenhouses usually receive less light for the same reason. Straight-side lean-to, slant-side lean-to, and curved-side lean-to styles are ideally suited for small, easy-to-construct attached greenhouses. A solid foundation similar to the house foundation is often required or highly desirable for attached greenhouses. Joining and sealing the greenhouse to the house needs special attention.