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The oval tube for greenhouse arches has become the standard in commercial greenhouse construction across Canada and North America, and for good reason. Stronger, more durable, and better suited to light transmission than round, square, or rectangular profiles, it represents a real agronomic and economic advantage for growers who choose their structure carefully.
Here are the five reasons why the oval tube is the best choice for greenhouse arches.
1. Superior Structural Resistance
Thanks to its unique geometry, the oval tube offers remarkable resistance to wind, snow, and heavy loads. Unlike round or square profiles, its cross-section allows it to withstand significantly more stress without adding extra weight. Your greenhouse stays stable and secure even under the most demanding weather conditions found in Quebec, Ontario, and across Canada.
For the same quantity of steel, the oval tube is:
- Approximately 50% stronger than a square tube (reference: elastic limit)
- Approximately 30% stronger than a round tube
- Approximately 20% stronger than a rectangular profile
These numbers are not trivial. They mean that at equivalent strength, you can use less steel, which translates directly into savings on both the structure and installation costs.
2. More Light for Your Crops
Because the oval tube is naturally stronger per unit of weight, arches can be spaced further apart without compromising structural stability. Fewer arches means less metal blocking the plant’s light exposure, and therefore more natural light available for photosynthesis.
This is not a minor agronomic detail:
“Most experienced growers and experts say that 1% more light in a greenhouse leads to approximately 1% more yield.” Corenthin Chassouant, Agronomist (MSc, Agr.), Horti Generation
For a commercial greenhouse growing tomatoes, strawberries, or leafy greens, gaining a few percentage points of available light represents a measurable improvement in yield per square foot across the entire season.
Wider arch spacing also reduces the number of components to assemble during installation, simplifying and accelerating the build.
3. Long-Lasting Durability
A greenhouse is a long-term investment. The durability of the structure is not optional. Oval tubes resist bending and twisting better than round, square, or rectangular profiles of the same weight. Combined with quality galvanization meeting ASTM A123 or CSA G164 standards, they maintain their strength for many years, reducing maintenance costs and avoiding premature replacement.
This is one of the reasons why serious North American manufacturers, who must meet the National Building Code of Canada (NBC) and equivalent US standards, favor oval tube profiles in their commercial greenhouse product lines.
4. Gentle on the Poly Film
One often-overlooked advantage of the oval tube is the absence of sharp edges. Square or rectangular profiles create friction points that wear down the polyethylene film prematurely, especially during movement caused by wind. The oval tube, with its rounded section, eliminates this problem entirely.
The practical result: less friction, fewer micro-tears, and a significantly longer service life for your plastic cover. Over multiple seasons, this means real savings on film replacement costs.
5. An Optimized Mechanical Profile
The wider, flatter profile of the oval tube increases bending stiffness compared to circular or square sections of equivalent weight. In other words, the oval shape extracts maximum performance from every kilogram of steel used in the structure.
This structural efficiency is particularly valuable in high-snow-load regions like Quebec, Ontario, and the Atlantic provinces, where greenhouse structures must meet rigorous design requirements to protect both the grower’s investment and the crops inside.
Oval Tube in Practice: Examples from Commercial Greenhouses
Harnois Greenhouses, a Quebec-based manufacturer recognized across North America, uses oval tube profiles throughout its commercial greenhouse product line:
- TunnelPro Plus: large high tunnels for berry production and field-scale vegetable growing
- Ovaltech: freestanding greenhouse for commercial controlled-environment production
- Luminosa: gutter-connected or multi-span greenhouses for high-value crop production
These three structures illustrate how the oval tube adapts to different scales and production types, from the three-season high tunnel to the permanent commercial greenhouse.
Conclusion
The oval tube is the most rational choice for commercial greenhouse arches. It delivers superior resistance per unit of steel weight, better light transmission, increased durability, and extended protection of the plastic film. Whether you are building a large high tunnel for berry production or a permanent commercial greenhouse, the oval tube combines structural performance and agronomic advantage in one proven solution.
Written by Corenthin (Félix) Chassouant, Agronomist (MSc, Agr.) and VP of Sales and Business Development at Industries Harnois. 10+ years advising commercial greenhouse producers across North America.
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