Comparing Poly Tunnels and Greenhouses

Poly Tunnel Vs Greenhouse

So you’re thinking of starting your own garden and now you’re faced with the decision of whether to invest in a poly tunnel or a greenhouse. Both options offer a controlled environment for your plants to thrive, but which one is the better choice for you? In this article, we’ll compare poly tunnels and greenhouses, exploring their similarities and differences, and ultimately helping you make an informed decision for your gardening needs.


Poly Tunnel

A poly tunnel, also known as a polyethylene tunnel or hoop house, is a type of structure used primarily for plant cultivation. It consists of a series of curved hoops made from plastic or metal, covered with a layer of polyethylene plastic. The plastic covering allows sunlight to penetrate while creating a protective barrier against unfavorable weather conditions such as wind, rain, and excessive heat.


A greenhouse is a controlled environment designed for the cultivation of plants. It typically has a framed structure made of glass or polycarbonate panels, which provide insulation and allow sunlight to enter. The enclosed space allows for precise control over temperature, humidity, and other environmental factors, creating an optimal growing environment.


Poly Tunnel Structure

Poly tunnels have a simple and flexible structure. They consist of curved hoops, usually made of metal or plastic, placed at regular intervals. These hoops are securely anchored into the ground, forming the basic framework of the tunnel. A layer of polyethylene plastic, often with UV protection, is stretched over the hoops and securely fastened to create a sealed environment.

Greenhouse Structure

Greenhouses have a more rigid and permanent structure compared to poly tunnels. They are typically built with a framework of aluminum, steel, or wood, which provides stability and durability. Glass or polycarbonate panels are then installed on top of the frame to form the walls and roof of the greenhouse. This solid structure allows for better insulation and protection against harsh weather conditions.

Poly Tunnel Vs Greenhouse


Poly Tunnel Materials

The main material used in poly tunnels is polyethylene plastic. This plastic is durable, lightweight, and relatively inexpensive. It allows for ample light transmission and can withstand various weather conditions. The plastic coverings may also have UV protection to extend their lifespan. The hoops can be made of metal, such as galvanized steel or aluminum, or sturdy plastic materials that are easy to assemble and disassemble.

Greenhouse Materials

Greenhouses utilize more diverse materials in their construction. The framework can be made of aluminum for its lightweight nature or steel for increased strength and durability. The walls and roof are commonly constructed using glass or polycarbonate panels. Glass provides excellent light transmission and is long-lasting, but it is heavier and more prone to breakage. Polycarbonate is a lightweight alternative that still offers good light transmission while being shatter-resistant and providing better insulation.


Poly Tunnel Construction

Poly tunnels are relatively easy to construct, making them a popular choice for small-scale gardeners and hobbyists. The assembly process involves anchoring the hoops into the ground and then stretching and fastening the polyethylene plastic cover over them. Some poly tunnels also come with pre-cut polyethylene sheets to simplify the construction process further. The lightweight nature of the materials allows for easy transport and installation.

Greenhouse Construction

Greenhouse construction can be more labor-intensive and time-consuming compared to poly tunnels due to its more fixed and permanent structure. The process usually involves laying the foundation, erecting the frame, and then installing the glass or polycarbonate panels. Greenhouses often require more specialized tools and equipment for proper installation, making them more suitable for commercial operations or dedicated gardening enthusiasts.

building a greenhouse


Poly Tunnel Flexibility

One of the major advantages of poly tunnels is their flexibility. Their lightweight structure allows for easy disassembly and relocation, making them popular among gardeners who frequently change their gardening locations or need to utilize temporary growing spaces. Poly tunnels can be adjusted or extended by adding or removing hoops and adjusting the plastic cover to accommodate changing growth needs.

Greenhouse Flexibility

Greenhouses, on the other hand, are more permanent structures and are not as easily moved or adjusted. Once a greenhouse is constructed, it is typically meant to stay in one location. While additions or modifications can be made, they usually require more significant construction efforts. Greenhouses are more suitable for long-term or permanent plant cultivation, where the need for flexibility is not as crucial.

Temperature Control

Poly Tunnel Temperature Control

Poly tunnels provide some level of temperature control. The polyethylene plastic covering allows sunlight to enter and trap heat during the day, creating a warm environment for plant growth. However, they lack the insulation properties of greenhouses, resulting in less efficient temperature regulation. In hotter climates, poly tunnels can experience higher temperatures, potentially requiring additional measures such as shade cloths or ventilation to prevent overheating.

Greenhouse Temperature Control

Greenhouses offer superior temperature control compared to poly tunnels. The glass or polycarbonate panels used in their construction provide better insulation, retaining heat more effectively during colder periods. Additionally, greenhouses can be equipped with various heating and cooling systems, such as heaters, fans, and ventilation mechanisms, to control the internal temperature throughout the year. This precise control allows for year-round cultivation of plants, regardless of external weather conditions.

GreenHouse Vent


Poly Tunnel Ventilation

Poly tunnels generally have less effective ventilation compared to greenhouses. They often rely on openings at both ends of the tunnel and vents along the sides to allow for air circulation. If these openings are not properly managed, the interior can become stagnant and prone to high humidity, which can lead to fungal growth or disease. Additional measures such as automatic vents or manually operating the openings may be necessary to maintain optimal airflow.

Greenhouse Ventilation

Greenhouses offer more advanced ventilation options. They can be equipped with automatic vents, fans, louvers, or roof vents that can be adjusted to regulate airflow. This flexibility allows for precise control over humidity and temperature levels, preventing the build-up of moisture or excessive heat. By managing ventilation effectively, greenhouses can create a healthier growing environment and reduce the risk of plant diseases.

Light Transmission

Poly Tunnel Light Transmission

Poly tunnels provide good light transmission due to their polyethylene plastic coverings. The plastic material allows sunlight to penetrate while diffusing it, promoting even lighting conditions for plant growth. However, it is important to note that the transmission rates may decrease over time due to the accumulation of dirt or damage to the plastic. Regular cleaning and maintenance are necessary to ensure optimal light penetration.

Greenhouse Light Transmission

Greenhouses, particularly those with glass panels, offer excellent light transmission. Glass has high transparency, allowing for maximum sunlight penetration. This promotes vigorous plant growth and enables the cultivation of light-demanding plants. Polycarbonate panels are also a popular choice as they provide good light transmission while being more impact-resistant than glass. The materials used in greenhouses help optimize light distribution and create an ideal growing environment for a wide variety of plants.

Glass Greenhouse


Poly Tunnel Cost

Poly tunnels are generally more affordable compared to greenhouses. The materials required for construction, such as polyethylene plastic and metal hoops, are relatively inexpensive and readily available. The simple design and lighter structure also contribute to lower costs. Poly tunnels are a cost-effective option for those on a limited budget or who require a temporary cultivation solution.

Greenhouse Cost

Greenhouses are typically more expensive due to the materials and construction methods involved. The use of glass or polycarbonate panels, along with a more substantial framework, can significantly increase the overall cost. Additionally, the need for specialized equipment and construction expertise can further add to the expenses. Greenhouses are often considered a long-term investment for serious gardeners or commercial growers who require a more substantial and durable structure.


Poly Tunnel Suitability

Poly tunnels are suitable for a variety of applications and users. Their ease of installation and affordability make them an excellent choice for home gardeners, hobbyists, or those with limited space. They are particularly useful for seasonal cultivation, as they can be easily packed away during the off-season. Poly tunnels are also suited for a wide range of plants, from vegetables and herbs to flowers and nursery seedlings.

Greenhouse Suitability

Greenhouses are best suited for those who require a more controlled and year-round growing environment. Their superior insulation and temperature control capabilities make them ideal for starting seedlings early in the season, extending the growing season, or cultivating plants that require specific climatic conditions. Greenhouses are commonly used in commercial agriculture, research facilities, and for growing delicate or exotic plants that may not thrive in outdoor conditions.

In conclusion, both poly tunnels and greenhouses have their advantages and suitability depending on the needs and preferences of the gardener. Poly tunnels offer flexibility, easy setup, and affordability, making them a practical option for home gardeners and seasonal cultivation. On the other hand, greenhouses provide better temperature control, ventilation, light transmission, and are suitable for more specialized or year-round cultivation requirements. Ultimately, the choice between a poly tunnel and a greenhouse depends on the specific goals, budget, and long-term plans of the gardener.

Comparing Poly Tunnels and Greenhouses