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Know Your Options When Growing Onions

Onions have existed for thousands of years, dating back to around 5,000 B.C., but they weren’t always used exclusively for food.

Ancient Egyptians worshipped onions, believing they would bring prosperity in the afterlife, and in the Middle Ages, they even were used as currency.

However, now onions are used for consumption.

Onions can grow in many ways, from seeds in the garden, transplanted from indoors or planted from sets. Onion sets are an immature onion bulb grown from a seed that was planted late in the summer of the previous year. These can be harvested in the fall and then are replanted in the spring.

If choosing to grow your crop from onion sets, pick the smallest sets because the larger sets tend to stop growing sooner, compared with the smaller ones. However, onion sets from the store usually only come in a few varieties.

Because of the many varieties of onions, the set selection at the store may not be ideal for your garden. By choosing to plant seeds, you will have a much larger selection.

Onions are a cool-season crop and take approximately 90 days to reach maturity. Planting seeds directly into your garden in the spring may not give the onions enough time to mature before the temperature gets too hot, so planting them inside under grow lights first may work well.

If you start onion seedlings indoors, plant them approximately 10 to 12 weeks before moving them outside because they are slow growing. Only leave the grow lights on for 10 to 12 hours per day so you don’t hinder the plant’s growth.

If you prefer to plant onions seeds directly into the ground, do so in late March or early April, as soon as the weather is warm enough and doesn’t dip below 20 degrees. Adding manure or compost to the soil before planting will be very beneficial to the plant because onions require a lot of mineral nutrients to thrive.

Onions technically are a root crop. However, when planting, think of them more as a leaf crop and only plant them about 1 inch below the soil.

For more information on safely growing, processing and selling onions and other specialty crops in North Dakota, visit NDSU Extension’s Field to Fork website at



Abigail Glaser, NDSU dietetics and management communication student

Julie Garden-Robinson, NDSU Extension food and nutrition specialist

Old Farmer's Almanac. (n.d.). Onions. Retrieved from

This project was supported by the U.S. Department of Agriculture’s (USDA) Agricultural Marketing Service through grant 14-SCBGP-ND-0038. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the USDA.

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