Learn what the difference is between long-day and short-day onion varieties, which one you should be growing, and my personal favorite varieties for easiest growing, long-term storage and fresh eating.
When I first started gardening, half a lifetime ago now, I reeeeeally wanted to grow onions.
Leafing through the seed catalogs made my head swim, though. There were all sorts of options for long-day, short-day and day-neutral varieties. There were more options for seeds and slips and sets. Walking onions, bunching onions, storage onions, sweet onions. I felt like I was in way over my head and decided to just skip growing onions altogether.
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Not to worry, though — I’ve learned a lot in the years since then. Today, onions are one of the easiest, most reliable and longest-lasting vegetables I grow. And it’s mostly thanks to finally understanding the right kind of onion to plant. Next week I’m going to talk more about the best way to start your onions, but first I wanted to really flesh out the different kinds of onion varieties available. My hope is that you won’t be as confused as I was about growing onions.
Let’s get to it!
Onion Varieties: Short-day vs. Long-Day
First things first is explaining the difference between short-day, day-neutral and long-day onion varieties. This is probably one of the most important things to know when it comes to choosing what to grow.
All onions require a certain amount of daylight hours to form. They’ll only grow those large bulbs (perfect for slicing onto hamburgers) if they get the right amount of daylight required for their variety.
Short-day Onions //
- Need 10-12 hours of daylight to form bulbs
- Mature in 75-110 days
- Grow best in the south
Day-Neutral or Intermediate-Day Onions //
- Need 12-14 hours of daylight to form bulbs
- Mature in 110 days
- Can be grown almost anywhere
Long-Day Onions //
- Need 14-16 hours of daylight to form bulbs
- Mature in 90-110 days
- Grow best in northern climates
It’s important to grow the correct variety of onion for your region. If you don’t, your onions will never grow to their full potential.
Yellow, White or Purple
Different colored onions were developed for different reasons, and you may want to choose your variety based on what they’re best used for.
Yellow Onions: These onions usually have a yellowish to brown colored outer skin, and white flesh. They are the most common type of onion available, and the best all-purpose onion to grow. They’re usually very pungent, but get sweeter and mellower when they’re cooked and add the most onion flavor to your dish.
White Onions: White onions are white, inside and out. They’re also usually very pungent and strongly flavored; however, some white varieties can be mild and sweet tasting. White onions also typically have crisp, meaty flesh and thin, papery skin.
Purple Onions: Purple onions have purple or red skins and white flesh with some purple coloration. They are usually mild tasting and not especially pungent. They’re great for eating raw in salads and salsas, although their layers can be tougher and less meaty than white onions.
Storage Onions or Sweet Onions
After picking day-length and color, you’ll also have to decide whether you want to be able to store your onions long-term or enjoy an incredibly sweet fresh onion taste immediately.
Sweet onions are just that — sweet. They’re high in sugars, mild tasting and perfect for fresh eating. Their skins are papery thin and they won’t last long past summer.
Storage onions, on the other hand, are bred specifically to last 6 months or more after harvest. You still have to properly cure them and keep them in a dark, cool place with good airflow, but do that and they will still taste crisp and onion-y long after other varieties have sprouted or gone moldy. This is because storage onions have a lower moisture content and higher levels of sulfurous compound, as well as multiple layers of thick protective skin.
Other Types of Onions
Flipping through the seed catalogs, you’ll probably also notice a few different kinds of onions that aren’t sweet or storage varieties.
Scallions: These are also called “spring onions,” “bunching onions,” and “green onions.” Any onion variety can be harvested as a scallion, although there are cultivars that were developed just for this use. Scallions are either picked immaturely, before a bulb has time to form, or has been bred to not form a bulb at all. They’re also mild tasting and perfect for use in salads and soups.
Walking Onions: Also known as “Egyptian onions,” “tree onions,” and “top-setting onions.” These onions are small and produced at the top of the plant instead of flowers. As they grow, they get heavier and bend the stalk of the plants. Once the baby onion bulbs touch the ground they root, grow and make new plants!
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Shallots: Shallots are in the allium family, but aren’t technically onions. They look like small, elongated onions on the outside, but like large garlic cloves on the inside. Their taste is mild, yet distinctive, with subtle hints of garlic. Shallots are excellent minced and added to vinegarettes and salads, or fried, roasted or caramelized in other dishes.
Cipollini: These onions have sort of a weird name, but they are just little, flattened onions. They have very thin skins that can be hard to remove, and a high sugar content which makes them very sweet tasting. Like other sweet onions, they don’t store well.
My Recommended Onion Varieties
Here on the Oregon coast where I live, summer days are long and the sun doesn’t set until almost 10:45 p.m. Our warm-weather growing season might only last 90-120 days, but those days can last 16 hours from sunrise to sunset! Long-day onion varieties definitely grow best here. These are the onion varieties I’ve had the best luck growing!
Storage onions //
- Australian Brown
Sweet onions //
- Walla Walla
- White Sweet Spanish
Other Types of onions //
- Guardsman bunching
- Evergreen bunching
- Lilia bunching
And that’s about it! Picking onions doesn’t have to be hard. Just make sure to pick the day-length variety that is best suited to your region, the color that appeals to you, and whether you want to be able to store your onions long term or use them right away.
What about you guys? What are your favorite types of onion varieties to grow?
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