Single-span greenhouse is a type of greenhouse structure characterized by a single, continuous roof that spans across the entire structure. The roof typically forms a curved or peaked shape, and the walls of the greenhouse may be either open or enclosed, depending on the design.

Here are key features of a single-span greenhouse:

1. Single Roof Section: Unlike multi-span greenhouses that have multiple sections or "spans" of roofs, a single-span greenhouse has just one roof that spans the entire width of the greenhouse.

2. Simplicity: Single-span greenhouses are generally simpler and less expensive to build compared to multi-span greenhouses because they don’t require as many structural supports or complicated framework.

3. Cost-Effective: They are typically more affordable for smaller-scale operations or for use in areas where space is limited.

4. Natural Ventilation: These greenhouses can often make use of natural ventilation systems (like roof vents or side vents) because of their simple design, which helps regulate temperature and humidity.

5. Size: They are usually smaller than multi-span greenhouses, though they can still cover a reasonable area depending on the needs of the grower.

Single-span greenhouses are commonly used for growing a variety of plants, including vegetables, flowers, and even small-scale commercial crops. They are popular in both home gardening and commercial agricultural operations due to their ease of construction and maintenance.