Testing Hemp as a Cover Crop in Vineyards

Started in 2019, “Hemp as a cover crop in New Zealand vineyards: a feasibility study,” tested the effect of hemp when used as a cover crop and intercrop for vineyards (1). Among the conclusions, viticulture researcher Mark Krasnow and vintner Kirsty Harkness stated that hemp grown in the vineyards helped improved the soil, did not negatively affect the vines, and improved the quality of the wine (1,2).

“I thought it was a good idea to trial a cover crop that we could potentially earn a second income from without disadvantaging the vines,” Harkness initially said, a year into the trial (2). “There are other benefits to the vineyard and environment we are discovering too. Due to our grapes already being a high value crop, we are doing trials to assess the impacts on vine growth, nutrition, and productivity of planting hemp in the interrow.”

The cannabis sativa cv Kompolti seeds were planted midrow in a Sauvignon blanc vineyard on New Zealand’s South Island (1). The hemp became established in the soil without supplemental nutrition or watering, even during a dry period (3).

Sample testing included petiole collection, canopy gap quantification, a harvest analysis that included testing to see if cannabinoids had possibly entered the grapes, and a soil analysis (1). Results from the first year of the study, Harkness noted, included the hemp attracting beneficial insects, weeds initially not growing through it, and its use as a ground insulator (2). The study noted in its conclusion that seed quality was highly important and that hemp as a cover crop was not a competitor to the grape vines (1). One area for further study, the authors noted, was the effect on the wine produced in terms of quality and flavor (1).

“It’s ability to survive with little water, its robust root system which adds carbon to the soil, and its ability to grow in and improve compacted soils, makes it a useful tool for vineyard management,” stated Krasnow (3).

The study was reportedly the first of its kind (2).

References

1. Krasnow, M.; Harkness, K. Hemp as a cover crop in New Zealand vineyards: a feasibility study https://issuu.com/ruralnewsgroup/docs/final_hemp_cover_crop_trial_report_for_nzw?fr=xKAE9_zU1NQ (accessed Oct 30, 2023).
2. Danenburg, E. World first industrial hemp study in vineyards taking place in Marlborough https://winetitles.com.au/world-first-industrial-hemp-study-in-vineyards-taking-place-in-marlborough/ (accessed Oct 30, 2023).
3. Bell, C. Hemp Study: vineyard cover crop works well. New Zealand Winegrower. 2023, 42.