New research report: Overwintering scallions with heavy rowcover

by Becky Sideman, UNH Extension

Scallion varieties, all lined up for a photo shoot.

After several years of research, we know that it is possible to plant bulbing onion (Allium cepa) in the fall, overwinter them in low tunnels, and harvest bulbs by late May in Durham, NH (see info about this system here). In response to grower inquiries, we expanded this work to look at non-bulbing onions, also known as green onion or scallion (Allium fistulosum). We were particularly intrigued by reports that growers successfully overwinter scallions using just row cover, no low tunnels involved.

What we did: We grew over a dozen varieties of scallions, planted at different dates, and protected them overwinter using heavy row cover. We then evaluated percentage of survival in the spring.

We found: that there were dramatic differences between varieties, and that some varieties survived very well in this system. We were encouraged enough to do some more work with this system to learn more!

Want all the details? Check out the full research report !

Scallions tucked in for the winter, under their 1.25 oz/yd2 row cover.