A tunnel greenhouse, which is often called an arch, is a semi-circular or semi-oval structure with a crescent roof, which is used to grow all kinds of flowers and ornamental plants, medicines and agricultural products.

Probably, when you talk about greenhouse farming, the first image that comes to your mind is the construction of a tunnel greenhouse with an arched roof and similar to a long tunnel. There are different types of greenhouses in terms of appearance, but most Iranian farmers are interested in building the tunnel model.

If you want to know the benefits of building this structure, its types, applications and more details, stay with us until the end of this article.

What is a tunnel greenhouse?

A tunnel greenhouse, which is often called an arch, is a semi-circular or semi-oval structure with a crescent roof, which is used to grow all kinds of flowers and ornamental plants, medicines and agricultural products.

In some cases, long greenhouses with angled walls but a dome-shaped roof are also called tunnel greenhouses. But some experts put this form of greenhouse in the Spanish type and consider it different from the tunnel model.

Tunnel greenhouses are the best option for growing vegetables, summer plants, ornamental and medicinal plants, but they are not the right choice for growing tall plants and short tropical trees.

In general, the height of this type of greenhouse varies from 2 to 4 meters depending on the environmental conditions and the type of product. Their width or opening is between 4 and 6 meters, which reaches up to 11 meters in some areas. But its length depends on the size of the land and the desired area of the farmer and is not fixed.

Types of tunnel greenhouse

The construction of the tunnel greenhouse has been divided into two single-unit and two or more-unit models based on the number of roof crescents. A single unit greenhouse has only one crescent, which is finally placed on the walls perpendicular to the ground.

But two or more units with more crescents and connected to each other are connected to the ground by two vertical walls on the sides. Of course, in this model, strong columns are considered between the arches of the roof, which support some of the weight of the greenhouse on the floor.

Despite saving money and being suitable for some of the same products, the multi-unit or compound type reproduces diseases and pests at a faster rate in all units. Also, it is impossible to control the conditions for several product models in it, and it is better for farmers to cultivate various crops by building a single tunnel greenhouse.

Application of construction of tunnel greenhouse

It is possible to grow all kinds of plants in tunnel greenhouses, but the best ones are:

Low height greenhouses such as short cucumber bushes, tomatoes, green beans, etc
All kinds of vegetables such as mint, basil, carrots, etc
Branched ornamental flowers
Shrub and tree apartment flowers
Medicinal Plants
Types of mushrooms

Advantages of tunnel greenhouse

The many advantages of building a tunnel greenhouse are the main reason for its popularity compared to other types of greenhouses. The most important strengths of these structures are as follows:

The construction of this place requires less capital than other models, and even farmers can save money by purchasing a second-hand tunnel greenhouse structure.
It is easier to set up than other models.
It is used to grow more crops needed by society.
It is possible to install its skeleton by various methods such as welding and bolts.
Its crescent roof directs snow and rain to the ground.
It has high resistance to wind and storm.
It can be installed with all kinds of available materials.
Its arc-like appearance maintains the temperature inside the space.
By creating a focal point for receiving solar energy and heating with its energy, it prevents fuel consumption.
It absorbs more light, so plants grow better in it.
The entrance and its appearance allow the traffic of agricultural machines and seed transportation.

Disadvantages of tunnel greenhouse

Along with the many advantages that the construction of a tunnel greenhouse entails, it has the following weaknesses:

Building natural ventilation and windows in it is a little more difficult than other greenhouse models.
In some cases, due to wrong engineering, a few centimeters of the roof of the greenhouse are made flat, which will cause the accumulation of snow and rain water.
suitable material

It is possible to build a tunnel greenhouse with a variety of common materials, but using the materials listed below will increase the durability and longevity of the structure:

The construction of metal skeletons, which are connected to each other with bolts and nuts, has the ability to be moved in addition to high endurance. The diameter of the metal rods depends on the size of the greenhouse and other influencing factors such as the climate of the region.
Polycarbonate coatings are the best choice ahead with higher resistance than conventional wide nylons, lower price and easier installation compared to glass coating.

For greenhouses with a small height and area that farmers do not intend to use for a long time, plastic pipes are also good choices. But the wooden skeleton is not used in the construction of the crescent roof of the tunnel greenhouse due to its low flexibility and high fragility.

Necessary equipment in the construction of a tunnel greenhouse

The necessary equipment in the construction of any greenhouse depends above all on the type of crops that can be grown and providing suitable conditions for plant growth by creating enough heat, cold or humidity.

But in general, due to the difficulty of creating natural ventilation in the walls and roof of the tunnel greenhouse, it seems necessary to install one or more suitable ventilation systems. Also, installing a heating and cooling system according to the climate of the region and the growing season is also a basic need.

On the other hand, it is better for farmers in areas with a direct radiation angle to use a movable canopy in the construction of a tunnel greenhouse for growing shade-loving plants.

The cost of setting up a tunnel greenhouse

The capital required to build a greenhouse with a crescent roof is not fixed for all cases and depends on the following factors:

The size of the greenhouse
type of skeleton
The type of top coating
Number, type and brand of necessary equipment
product type

final word

Building a tunnel greenhouse for growing many plants is a worthy choice that has many advantages. In this article, by introducing the crescent roof greenhouse, we have provided you with useful information about its advantages, disadvantages, costs and other details.