Last weekend I was preparing for dinner guests, and shortly before my guests arrived I was chopping onions for soup. When I was half way through the first onion my eyes were red, puffy, and dripping with tears. Then the doorbell rang and I greeted my guests looking like I was in the full throes of emotional breakdown. Although syn-propanethial-s-oixde (that's the chemical that brings the tears) in onions makes me teary, I love them and can't live without them. My love of begins long before they reach my kitchen because I love growing onions in my backyard garden.
Variety is the spice of life--and onions
Let's clear up some onion terms.
Allium is the genus for all onions.
There are many species within that genus. Allium cepa is the common bulb onion. Bulb onions come in fantastic varieties that include white, red, and yellow.
Allium aschaninii, allium cepa var. aggregatum, and allium ascalonicum are shallot varieties, which are sweeter than bulb onions.
Scallions are the thin green shoots you harvest when you thin onion seedlings.
Egyptian onions (a.k.a. tree onions, walking onions, or winter onions) are a perennial variety that are self propagating.
Chives are technically not an onion but rather an herb with an onion flavor.
How to grow onions? You have 4 choices
Gardeners have four choices to make when deciding how they'll grow onions. Will you start your crop from seed, bulb sets, transplants, or replant sprouted onions?
1. Starting onions from seed. Most seasoned gardeners agree that while starting onions from seed is not impossible, it is the most challenging of the four options. While most seeds will remain viable for a few years, onion seeds have a short shelf life. So, use them within the first year or two. If you choose to start from seed here are some tips:
Fill small plastic growing cells with quality potting soil. They should be almost, but not completely, filled. Sprinkle the small onion seeds on top of the soil (2-3 seeds per cell) and then cover with a sprinkle of more soil. Gently water the cells.
Starting these seeds in a green house is highly recommended because you can control growing conditions. Be sure to harden off the seedlings before transplanting outdoors.
2. Growing onions from bulb sets. The easiest way to grow onions is to start with bulb sets. These are small, dry onion bulbs that were grown the previous year. (See more on growing onions from bulbs below.)
3. Growing onions from transplants. Transplants are seedlings that look like soft green hair. They have not yet developed bulbs. Treat these seedlings as you would other seedlings and plant outdoors when the ground can first be worked in the spring.
Once the shoots are a couple inches high thin them so they have 2-3 inches between them.
4. Growing onions from food scraps. If you have a bag of onions in your pantry that have started to sprout green shoots, you can plant them directly in your garden or a container.
Trim off the bottom inch of the onion (the bottom is the end that has the roots coming out of it--not the end with the green shoots) and plant in a 12 inch pot or directly in the garden. It will grow well indoors or outside.
Planting onions in 3 steps
Based on my own experience and conversations with fellow gardeners, growing onions from bulb sets is the option that most of us choose.
You will buy these sets at your local nursery, and when you get them home they're ready to plant.
1. Dig a hole in a sunny location. Some onion growers use a bulb planting tool to dig a hole for their onion bulb. Because I like to get dirty in my garden I simply use my hand to dig a hole that is big enough for the bulb. Don't bury them too deep; there should only be an inch of soil on top of the bulb.
Onions appreciate quality soil with compost, but don't over fertilize them. Aim for your soil to have a pH of about 6.5. Add calcified seaweed or lime to raise the pH level if necessary.
Onions don't want too much nitrogen because this encourages growth of the green shoot and not the bulb underground. Have you grown corn in your garden? Once the corn harvest is cleared out plant onions in that growing space because the corn will have used up most of the nitrogen.
2. Feed your onion plants with an application of compost every 4-6 weeks. Onions will grow fine with an inch of water per week.
3. When the green shoots grow to about a foot tall, trim them back to a four-inch height. This will send more growing energy down to the bulb and help prevent wind damage. Don't waste the shoots you trimmed. Use them in stir fry, veggie dip, or soups.
Growing onions while preventing pests
You're not the only one who likes onions; tiny thrips like them as well. I learned a handy tip from The Old Farmers Almanac regarding thrips. It suggests placing a dark sheet of paper under the onion plant and gently shaking the plant. If there are thrips, they will fall onto the paper. You'll be able to see their light tan colored bodies against the dark paper.
If you have thrips, treat the plants with an insecticidal soap.
A wet growing season may encourage onion maggots. They'll be found at the base of the plant. To prevent these nasty critters cover your onions with mesh netting. Be sure to mound dirt on top of the netting at its edges to seal it.
Later in the growing season you'll notice that your green onion tops start to droop and fall over. You'll also see the bulbs starting to bulge out of the ground. Resist the urge to harvest the onions at this time, and let them remain in the ground for another couple weeks. During that time the tops will continue to fall over even more, and they'll loose their green color.
If all of the tops haven't fallen over at this point, gently push them over.
Pull the onions out of the ground while keeping the green shoots attached. It's best to do this when the soil is dry to prevent excess moisture which will lead to rot. Lay the onion harvest to rest on garden soil (or other safe outdoor space). Remove any onions that are soft or with visible insect damage or rot.
Leave the onions on the ground for a few days. Make sure that they're not too crowded so that air can flow between the bulbs. If you live in an especially warm area, cover the harvest with a sheet while they're on the ground.
As you pick up the onions to move them inside to continue drying, gently squeeze each onion and discard any that are soft. (Don't waste these onions; use them immediately.)
Let the onions dry in a protected area such as a garage or garden shed until the roots become wiry and the outside skins rattle. Then store in a mesh bag in a dark area such as a pantry or closet.
Nutritional highlights & pesticide concerns
Although onions appear on the Environmental Working Group's long list of veggies that have pesticide residue, they are low down on that list. Never the less, I argue for growing your own onions using organic practices to completely avoid those nasty chemicals.
Onions are high in vitamin C and fiber. They are low in calories and free of sodium, fat and cholesterol.
I love old time-y garden wisdom so this verse from The Old Farmers Almanac made me smile:
Onion's skin very thin,
Mild winter coming in;
Onion's skin thick and tough,
Coming winter cold and rough.
Recipes that celebrate onions
Now that you've successfully grown onions you'll want to celebrate them in delicious recipes.
Image by John Klein. Food styling by Laura Klein
This veggie burger shows off hearty kale leaves as well as onions. It’s yummy and it’s packed with goodness–beans, quinoa, and kale. (Oh my!)
Image: Emily Monaco
Not only does this recipe show off onions, it also celebrates protein-rich spelt. Healthy, check. Scrumptious, check. Gorgeous, check.
Top image: jules
IMO, caramelized onions improve any recipe. That's why I especially love these recipes that put them front and center.
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lead image of onions via Shutterstock