Updated May 2025

In this previous post, we offered a few tips from Jackie Smith of the University of Minnesota Extension Master Gardeners of Carver and Scott Counties on growing vegetables. Jackie’s comments came during a presentation on growing unusual—or, more accurately—underused vegetables in northern gardens.

While the most popular vegetables to grow are tomatoes, cucumbers, peppers, beans and lettuce, many more vegetables grow well in our climate and many of them can be stored into the winter season. Jackie offered a long list of options, but here are five that you may not be growing, but should try.

Grow these underused vegetables in your northern garden

• Sweet potatoes. Plant sweet potatoes around June 1 for harvest in October. While the leaves are mainly ornamental, each plant produces 4 to 5 delicious spuds when allowed to grow. Harvest as soon as the leaves are nipped by frost, cure the potatoes two weeks in a warm place and then store them; they will last all winter.
  • For an advanced tip, save slips from the plants, root them in potting soil and save them for the next year. They will root and hang on but not grow much through the winter, then grow impressively once the warm season arrives. 
• Fennel. Northern gardeners can’t really plant fennel until well into June, because it requires warm soil. As a result, you may not always get the full round bulbs that taste like anise. If you do get them—enjoy! If the plant bolts, no worries; instead, use  the ferny foliage and fennel seeds as herbs to add a delicious, exotic flavor to dishes.
• Luffa. Also known as Cee gwa or Chinese okra, luffa is sometimes described as “zucchini with a taste.” Start seeds indoors in April and plant them out in June. After the plants flower, you will see a gourd growing behind the bud, just like zucchini. Gardeners can harvest those young (under 6 inches) and stir-fry them, but you may also let a few fruits get big and dry on the plant to grow your own sponges, or “luffas”.
• Mustard greens. If you like a little kick in your salad, try growing mustard greens. These are easy to grow and work well in beds where you are combining ornamental and edible plants. Sow seeds outdoors anytime between May 15 and July 15 and begin harvesting in June, continuing on through November. Recommended varieties include ‘Osaka Purple’ and “Giant Red’ for biting, but not overpowering flavor.
• Fall radishes. While you can certainly grow a respectable radish in the spring, those harvested in the fall tend to be bigger and more flavorful. Plant between July 15 and August 15 and give the radishes 4 to 6 inches between plants. They need it, because these radishes tend to get larger. Don’t harvest until the roots are at least 2 inches across. They can stay in the ground until temperatures are dropping into the 20s.  Recommended varieties include ‘Red Heart’, ‘Rose Heart’ and ‘Summer Cross’ varieties for fall growing.

Which unusual vegetables do you enjoy growing?

Mary Lahr Schier is a Minnesota gardener, writer and editor and author of The Northern Gardener, From Apples to Zinnias, 150 Years of Garden Wisdom (Minnesota Historical Society Press, 2017), winner of the Silver Award of Merit from GardenComm in 2018. For 18 years, she edited Northern Gardener magazine, the publication of the Minnesota Horticultural Society and the only magazine dedicated to gardening in USDA Zones 3, 4 and 5..

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