How to Build a Multi-Span Greenhouse: Common Material Types and Key Selection Points

Multi-Span Greenhouses: The "Big Guys" of Protected Agriculture

When it comes to greenhouses, many people first think of the single-span arched houses lined up in a row. In fact, on large-scale planting bases and seedling factories, what you see more often are multi-span greenhouses - that is, several greenhouses connected together with the dividing walls removed to form one large growing space. They offer high space utilization and are convenient for mechanized operations and environmental control, making them suitable for vegetables, flowers, seedling cultivation and other production. They are also one of the protected agriculture facilities being promoted in various regions.

Greenhouse Materials Fall Into Two Main Categories: Frame and Covering Materials

A multi-span greenhouse is mainly composed of a frame and covering materials. Whether the materials are well chosen directly determines how many years the greenhouse can be used.

First, the frame. At present, the mainstream options are hot-dip galvanized steel pipes and hot-dip galvanized steel frames. After galvanizing, the surface is not easy to rust, and their load-bearing and wind-and-snow resistance are stronger than ordinary steel. When purchasing, check whether the galvanized layer is uniform and whether the welding and connectors are standard. These details determine the overall service life of the greenhouse.

Next, covering materials. There are three common types: first, plastic films, such as PO film and EVA film, which are low in cost, good in light transmission and easy to replace, making them the first choice for most growers; second, PC sun panels (polycarbonate panels), which are impact resistant and have decent insulation, and are often used in seedling greenhouses and other places with higher requirements for appearance and durability; third, glass, which offers stable light transmission and a long service life, but is expensive and places high demands on the frame, so it is mostly used in high-standard greenhouses.

When Choosing Materials, Don't Focus Only on Price

Many people compare only prices when building a greenhouse, only to run into problems after a year or two of use. It is advisable to consider several aspects comprehensively: first, the local climate. In areas with strong winds and heavy snow, choose frames and covering materials with stronger wind-and-snow load resistance; second, the type of crops grown. Leafy vegetables and high-end flowers have completely different requirements for insulation and light transmission; third, supporting equipment. Multi-span greenhouses often need ventilation, shading, water and fertilizer systems, so interfaces should be reserved when buying materials.

One more reminder: different regions have different support policies for protected agriculture construction. Subsidy standards and application procedures should be based on information published by the local agriculture and rural affairs department or agricultural machinery authority. Before building a greenhouse, it is worth asking first, as it can save quite a bit of money.

In short, a multi-span greenhouse is a long-term investment. If the materials are chosen correctly, later management is easier and yields increase. When purchasing greenhouse materials, look more, compare more and ask more, and make decisions based on your own plot conditions and planting plan, so that the greenhouse's benefits can truly be brought into play.