The findings come as the local table grape industry continues to operate at scale, exporting close to 80 million cartons annually, according to the South African Table Grape Industry (SATI).
In a trial conducted in Klawer on Sable Seedless grapes, treatment with the Kelpak biostimulant delivered a 27% increase in yield and improved berry size distribution.
Applications were made at key stages of vine and berry development, with benefits observed at harvest and after storage.
Post-harvest assessments following 20 days of cold storage also showed improved rachis condition, with more bunches retaining the green colour required for export markets.
South Africa’s table grape sector is heavily export-driven, with Europe and the UK accounting for more than 70% of shipments, placing emphasis on consistency, shelf life and visual quality.
Improvements in berry size and uniformity can directly influence pack-out rates and export value.
“What these trials show is that relatively small interventions at the right stage of development can translate into meaningful gains at harvest,” says Linda Greyling, head of technical support at Kelpak.
“In table grapes, even small improvements in berry size and uniformity can significantly increase pack-out and export value for producers.”
The product used in the trial is derived from the brown seaweed Ecklonia maxima, processed to retain bioactive compounds that support root development and nutrient uptake.
Greyling says consistent results across trials are key to adoption: “We are seeing similar trends across multiple trials - improved yield, better sizing, and enhanced quality. That consistency gives producers confidence that these outcomes are repeatable under commercial conditions.”
With rising input costs and environmental pressures, producers are increasingly focused on improving output without expanding planted area.
The trial results point to a growing role for biostimulants in supporting yield and quality under variable growing conditions.
