Which of the following is NOT a main type of greenhouse?

In the context of greenhouse types, it's essential to understand that the more commonly recognized types include lean-to, freestanding, and attached greenhouses.

Lean-to greenhouses are those that are built against a wall of another structure, allowing them to share heat and space. Freestanding greenhouses are standalone structures not connected to any other buildings, providing flexibility in placement and design. Attached greenhouses, similar to lean-to types, are connected to another structure but typically emphasize added space for adjacent buildings.

The term "detached," while it might suggest being separate from other structures, is not generally recognized as a main type of greenhouse in horticultural terminology. The correct categorization of greenhouses usually focuses on their structural relationship to buildings (like lean-to or attached) or their independence (like freestanding). Therefore, the option labeled as detached does not fit within the traditional classification system of main greenhouse types. Understanding these definitions clarifies why detached is not considered a main type but rather can be a descriptive term applied to certain greenhouse configurations not formally recognized as a primary category.