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← Back to Discoveries | 2026-07-28 synthesized

Seaweed spray and hand-thinning cut synthetic hormone use in grapes

Crop Improvement

If you grow grapes on a backyard arbor, this points to seaweed extract and simple bunch-thinning as ways to get plumper, sweeter fruit without reaching for synthetic growth hormones.

Table grape growers usually spray vines with a synthetic hormone called gibberellic acid to make seedless grapes bigger and better looking, but it's costly and some growers want to use less of it. This study tested whether a natural plant compound called 24-epibrassinolide, a seaweed extract, and simply removing some grape clusters by hand could do part of that job instead. The combination improved berry size, sugar levels, and overall grape quality, showing that a mix of natural inputs and old-fashioned pruning can stand in for some of the synthetic spray.

Key Findings

1

24-epibrassinolide and seaweed extract, when combined with cluster thinning, improved berry size and quality in 'Thompson Seedless' (H4 strain) grapes

2

The natural treatments served as partial substitutes for synthetic gibberellic acid, a hormone conventionally used to enhance seedless grape development

3

Cluster thinning played a key role alongside the biostimulants in boosting fruit quality metrics such as size and sugar content

chevron_right Technical Summary

Grape growers may be able to cut back on synthetic gibberellic acid, a hormone spray widely used to plump up seedless grapes, by combining natural plant extracts with simple hand-thinning of grape clusters. Researchers found that treating 'Thompson Seedless' vines with 24-epibrassinolide or seaweed extract alongside cluster thinning produced grapes with better size, sugar content, and quality, offering a lower-input path to the same result.

hub This connects to 11 other discoveries — Thompson Seedless grape, seaweed crop-improvement, pruning, plant-signaling +1 more 5 related articles

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