Purpose
Authors: Kendra Workman and Sarah Papp
Plastic contamination from support twine and clips for high-wire vegetable production currently limits options for end-of-season vine management. The use of compostable alternatives for twine and clips may enable alternative management avenues for vines such as composting, anaerobic digestion and land-application; thereby reducing the amount of organics sent to landfill. While compostable alternatives are available, many growers remain hesitant due to concerns around durability, crop reliability, availability, and cost.
Trial details
This 4-month (December – April) high-wire cucumber trial evaluated commercially available compostable clips and twine under real greenhouse production conditions to determine whether their performance compares to standard plastic products.
Products Evaluated
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Figure 1: Evaluated clips
- Bato AMA 22 mm compostable clip (AMA 2) (Left)
- Bato AMA 21 mm compostable clip (AMA 1) (center)
- Conventional polypropylene clip (right)
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Figure 2. Evaluated twines
- AMA sisal compostable twine (top)
- BASF compostable twine (2nd)
- Polypropylene twine (control) (3rd)
- AMA jute twine (bottom)
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Key Findings
The compostable products maintained crop support throughout the full 4-month highwire cucumber production cycle with minimal breakage, stretch, or operational issues.
Twine Performance
Twine break force was measured on a sample of twine at the start, middle and end of the trial. Twine break forces remained unchanged before and after the trial, indicating that all twines tested maintained their strength throughout the trial.
Polypropylene twine samples (control) exhibited break forces of 26-33 Kg.
The AMA sisal and BASF compostable twines had the most similar performance to polypropylene twine and exhibited break forces of 20-28 Kg across the trial.
AMA Jute string showed occasional visual defects including fraying and mould, and a lower break force (14-19 Kg), but no failures occurred throughout the entirety of the production trial.
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Clip Performance
Both Bato compostable clips performed well during the trial with no major durability concerns observed during cucumber production. Overall, the Bato AMA 22 mm compostable clip showed the closest overall performance to conventional polypropylene clips.
Main Take Aways
Select commercially available compostable greenhouse clips and twine provided reliable crop support and strong durability under highwire greenhouse cucumber production conditions. While break force varied by material, all tested materials successfully supported the crop throughout the trial.
As product availability and costs improve, compostable greenhouse supports may become a practical pathway for reducing agricultural plastic waste without compromising crop reliability, thereby saving costs on tipping fees and landfill waste.
Funding Acknowledgements
The research was generously funded by Agriculture and Agri-Food Canada and the Sustainable Canadian Agricultural Partnership through the Clean Technologies program.