On farm evaluations of novel methods to increase garlic marketable yield

View the project final report

Commodities

• Vegetables: garlic

Practices

• Crop Production: postharvest treatment, vernalization (preplant chilling)
• Education and Training: on-farm/ranch research, participatory research

Small-acreage, local vegetable farms provide healthful food, taxable income, and ecosystem services to their communities. This project seeks to help sustain these farms by improving the yield of hardneck garlic, an economically important crop grown on many Minnesota vegetable farms. The project has both preharvest and postharvest components. To offset the increasing unpredictability of cold weather on garlic yield, we tested the effectiveness of preplant vernalization as a supplement to natural field chilling on garlic yield. For three years, ‘Chesnok Red’ and ‘Music’ garlic was vernalized for 10 d or 20 d at 40 F prior to planting at the University of Minnesota and at collaborating farms, and weights of cured bulbs were compared to that of unchilled controls. Vernalization was not effective in the first year, and only effective for ‘Music’ in the second year of the experiment. It may therefore be worthwhile for farmers to vernalize ‘Music’, but not ‘Chesnok Red’ bulbs for 20 d or more prior to planting to hedge against warm winter temperatures. To learn how modern hardneck garlic shelf-life is affected by storage temperature, on-farm and laboratory-controlled comparisons of ‘Chesnok Red’ and ‘Music’ bulb weight loss at 32 F and 40 F were done. Bulbs stored at 32 F lost 5-7% of fresh weight, whereas bulbs stored at 40 F or higher temperatures, lost 35-40% fresh weight. None of the ‘Chesnok Red’ (vernalized or control), while less than 10% of the control and 67% of the vernalized ‘Music’ bulbs that had been stored at 32 F and transferred to room temperature sprouted, by 2 months after the transfer. Bulbs stored at 40 F started sprouting after 9 months while in cold storage. Farmers who are selling garlic for consumption should store garlic at < 40 F, but farmers selling to others interested in planting garlic should store garlic at > 40 F.

The project has two objectives: 1) determine how to adapt vernalization practices used in the southern USA to grow garlic in northern climates, and test the practice on multiple Minnesota farms with different varieties of garlic, and 2) learn how well postharvest storage recommendations translate to actual farming situations and how on-farm postharvest practices affect possible shelf-life at market.