Many South African farmers view commercial greenhouse farming as an opportunity to boost profitability, maintain crop consistency, and to supply produce throughout the year without seasonal constraints. An obvious question that often comes to mind is: How much does a commercial greenhouse cost?
Well, determining the cost of your actual greenhouse structure is one thing (we’ll discuss greenhouse structure types and their respective impacts on productivity shortly) but there are various other factors that come into play when conducting a feasibility study for your unique greenhouse farming operation.
Whether you’re looking to diversify your existing farm, or start a completely new greenhouse farming operation, there are some obvious external factors that will determine whether you’re limited or unrestricted in the choice of your greenhouse structure design.
These include the availability of space, climate, and location based logistics. Of course, these factors will ultimately have an impact on your investment spend.
Perhaps the most important consideration is the type of crop you’d like to grow. This, combined with the external limitations discussed, will shed light on the internal greenhouse factors that need to be addressed to varying degrees for your unique requirements, and the resulting costs thereof.
These internal factors include the following:
All these factors combined (external, crop type and internal) have a direct impact on the investment required to get your commercial greenhouse up and running, and therefore, future productivity.
Long-term thinking is a must when weighing up commercial greenhouse farming costs. The initial investment may seem sizable, but the long term benefits of optimised crop yields and productivity may be substantial enough to make this investment a no brainer.
If the capital available for investment is limited, it’s important to start your greenhouse development with expansion and growth in mind. Ensure you invest in a system that enables scaling for higher yields and productivity in the future through means of adding more advanced technology down the track.
The combination of these external and internal factors will also have a direct bearing on which types of greenhouse structures to consider in your situation. And they themselves, are an important factor in your long term cost/profitability projections and decision making process:
When considering greenhouse cultivation, we think of efficiency in crop production, resources, space, labour, consumable costs and the list goes on… but one thing that can and will make all the difference in optimal yield performance is greenhouse structure design.
Studies have shown that there is a direct correlation between optimal yield performance and greenhouse structure design i.e. size, shape, height etc.
Reference: E. du Plessis (Masters of Science in Engineering, 2016)
Plastic greenhouse tunnels were only introduced towards the end of the twentieth century and became popular because of their low cost and ease of construction. Used in large commercial farming operations, varying qualities and thicknesses of plastic are available. The tunnels are also available in 6, 7, 8, 10 and 12m widths with 30 to 60m lengths and can be constructed as single span (standalone) or multi-span (joined) structures.
Recently there has been a focus on developing greenhouses with higher gutter heights. Glass greenhouses are constructed with a gutter height of 6 m and plastic covered greenhouses going up to 3.5-5 m. This has been shown to significantly improve the growing environment for greenhouse crops (du Plessis, 2016).
The structural design of greenhouses also influences the energy efficiency of a system. A study done by Djevic and Dimitrijevic (2009) showed that the type of structure can influence energy input per kg of product, energy efficiency and the productivity of a system with multi-span greenhouses being more energy efficient than single tunnel greenhouses.
Herbert Stolker, grower consultant to a number of our top South African growers shared his statistics on yield performance:
The statistics make it clear that different greenhouse structure designs create different microclimates that can counter varying weather conditions, promoting optimal growing conditions as a result.
Below is a rough estimate comparing heated to unheated greenhouses depending on the region's climate.
The first number is for Gauteng and Western Cape. Coastal Areas in brackets.Year estimates kg per m2
| Tomato 120-160 g | Blocky Pepper | English Cucumber | |
| Low cost tunnel (heating): | 28 | 14 | 22 |
| Low cost tunnel (no heating): | 23 (25) | 20 (22) | 10 (11) |
| Automated multi-span greenhouses (heating): | 50 | 25 | 57 |
| Automated multi-span greenhouses (no heating): | 36 (40) | 18 (20) | 41 (45) |
These figures show the experience and results of South African growers and could help you make an informed decision when selecting your commercial greenhouse.
Low cost tunnel structures can range between R200-300 per m2, whereas multispan structures can be anything from R300-R600 per m2, depending on the level of automation and ventilation required.
As you can see, answering the question, “How much does a commercial greenhouse cost?” is not as straightforward as one might hope for but whether you're an experienced farmer or new grower, hopefully the picture is becoming a little clearer.
Your unique situation may require some expert advice to guide your decision making progress and save on costs. Feel free to contact Bosman Van Zaal South Africa to receive further assistance in this regard. With almost a century of experience internationally, we are recognised as South Africa’s market-leading commercial greenhouse engineers with the in-house knowledge and expertise to bring your vision to life in every crop and protected horticulture need.
Bosman Van Zaal has 90 years of experience in the development and construction of greenhouses and over 40 years' experience with technical systems for international horticulture.
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