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Pros and cons of poly, glass and geodesic domes

Select the best structure for your agricultural needs, climate and budget.

A greenhouse’s goal is to create the perfect microclimate for plant growth. This involves a delicate balance of temperature, light, and humidity with the climate outside. It’s no surprise that greenhouse designs and coverings vary according to climate, weather patterns and plant requirements, and the choice of greenhouse covering is deeply tied to crop yield.  

Today, we delve into the pros and cons of three of the most popular – polyethylene (poly), glass, and geodesic domes – to guide you through making the best choice for cultivation.  

Poly Greenhouses: The Flexible Choice

Poly greenhouses are a cost-effective and flexible solution for many farmers. Their signature gothic roof design isn't just for show; it’s essential for tensioning the plastic covering over the structure and preventing sagging and accumulation of water or snow.

Poly structures are particularly suited for warm climates with an emphasis on cooling rather than heating. They offer a super efficient way to protect crops from excessive heat. 

Poly is the preferred covering for South African growers focused on commercial cultivation. By connecting multiple spans of poly greenhouses with gutters, a vast area becomes accessible for cultivation. This approach optimises both cost and functionality, ensuring large-scale operations can thrive. For example, this multi-span project we built at Emseni in Kwazulu Natal


  • Its cost-effectiveness offers a budget-friendly alternative to glass.
  • The material’s flexibility makes it suitable for a variety of structural designs.
  • In warm climates, poly's lesser insulation property is an advantage, making temperature regulation easier.


  • Poly provides less insulation, which can lead to higher heating costs in cooler environments.
  • Despite advancements, poly may not match the longevity or clarity of glass.

Glass Greenhouses: The Classic Choice

The quintessential image of a greenhouse is often one of gleaming glass panes—the Venlo glasshouse structures being a prime example.  

Glass offers optimal light conditions and insulation, and is favoured in colder climates or for growers who prioritise durability and light transmission. But these benefits come at a cost. 


  • Superior insulation properties make glass ideal for cooler climates or year-round cultivation.
  • Durability and longevity are unmatched, with glass structures standing the test of time.
  • High-light transmission promotes optimal plant growth.


  • The cost of glass and the necessary structure to support its heavy weight can be prohibitive.
  • Glass's excellent insulation can lead to overheating in sun-rich environments, necessitating additional cooling measures.

Geodesic Dome Greenhouses: The Aesthetic Choice

Geodesic domes captivate aesthetically, offering a unique, architecturally beautiful approach to greenhouse design.

They serve well in small-scale applications where the focus is on the visual impact rather than agricultural productivity. Their practical limitations usually lead to the domes not being sought after for commercial growth.


  • Aesthetically pleasing, these structures are often used in botanical gardens or educational settings.
  • The dome shape allows for even light distribution and an interesting interior space.


  • Scalability and practicality for commercial use are limited due to construction and maintenance costs.
  • Large-scale climate control within a dome can be challenging and less efficient than in traditional greenhouses.

Make the Right Choice for Your Greenhouse

Selecting the appropriate greenhouse structure and covering is crucial for maximising crop yield and operational efficiency. With agronomic and engineering expertise spanning continents and climates, Vegtech Netafim is your ally in creating spaces where plants don't just grow… they thrive. Get in touch with us on +27 21 987 6980 or to see how we can help you grow more with less.