Growing Onions

by Stephanie Suesan Smith on August 2, 2010

Onions right out of the garden make some of the best eating available.  They are high in vitamin C and taste wonderful.  While onions are not too complicated to grow, there are some things you need to know to get a good crop.Onions come in long, medium, and short day varieties.  While we think of the days as longer at the equator, that is only true in the winter.  In the summer, the hours of sunlight increase the further north you go.  That means people along the Canadian border need to grow long day varieties while people in Texas grow short day varieties.  Long day onions need 14-16 hours of sunlight a day.  Medium day onions need 12-13 hours of sunlight a day, and short day onions need 11-12 hours of sunlight a day.  Get the wrong type of onion and you won’t get much of a crop for your trouble.

Onions can be grown from seeds or from sprigs.  Most people purchase springs from the feed store or nursery at the appropriate time for planting.  Around here, they come in bundles of 25 or so sprigs.  You dig a shallow trench the length of your row as soon as you can work the soil in the spring.  Then lay the onion sprigs in the trench.  Cover up the trench and you should have a row of sprigs standing up, ready to grow.  Water them in and you are done.

The only problem with that is that you do not get many choices about what varieties you plant, and you do not know how they were treated.  By that I mean if you run an organic garden, you do not know how the sprigs were treated so they cannot be called organic.  There are some places to buy organic sprigs, but they are expensive as all get out.

The other option is to plant the onions from seeds.  You have to plan ahead a lot further to do this.  Where I live, you plant seeds in October.  They grow some before the cold weather, then go dormant until spring.  You cover them with straw to keep them warm.  In January, you uncover them and the onions start growing again.  They are ready for harvest at the usual time, around May.  You can get organic seeds from places like Seeds for Change, or regular seeds from the seed catalogs.  Onion seeds are tiny and hard to handle.  Some places sell them in a tape, which you bury with the seeds.  Otherwise, you just do the best you can and thin the resulting seedlings.

Seeds are planted 1/4 inch deep and 1 inch apart.  When they are about 6 inches high, thin the seedlings to one every two to three inches.  You can eat the ones you pulled out as green onions, or plant them in another row as transplants.  Transplants are put 3/4 inch deep and three inches apart.

Like most plants, onions appreciate some fertilizer.  Two to three pounds of fertilizer spread over a 100 square foot area of the garden, then raked into the soil, makes the onions happy.  Be careful with rake and hoe near the onions — you do not want to damage the onion root.

Watering should be done once or twice a week, depending on the drought conditions.  Onions grow best if watered slowly and deeply, so drip irrigation is the best way to do that.  In any case, an inch of water each time you water is best.  Make sure you keep the weeds pulled so they do not steal water from the onions.

Fertilize the onions again when they have five to six leaves.  One half cup fertilizer for each ten feet of row is good.  Side dress the onions, which means scatter the fertilizer between the rows.  Then water it in.

Onions are remarkably free of insects and diseases.  Tiny thripes may infect the center of the leaves, but Sevin, sulfur, or BT will kill them.  Sometimes onions get brown leaf tips or brown spots.  Sulfur can help this as well.  Be sure to read the label and follow it for all pesticides, even organic ones.

Onions are generally ready to harvest in May or July, if planted in January as transplants or October as seeds.  When the tops droop and fall, the bulbs are ready.  Let cure a day or two more in the ground, then store in an airy, dry place or in the refrigerator.

What kinds of onions do you grow?  Do you have any questions about how to grow them after reading this article?  Join the conversation and leave a comment.

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Available in print or ebook from or other retailers, this book walks you from choosing the site of your garden all the way through what to do after the harvest. Buy a copy for yourself or a friend today! 

{ 8 comments… read them below or add one }

Calgary Web Design August 2, 2010 at 9:38 pm

Talking about onions,I remembered my school days wherein we have to experiment on growing onions. It’s really cool and amazing observing them to grow.


Matthew Hamilton August 4, 2010 at 4:17 am

I have never attempted to plant onions – though this very informative post will certainly have me on my way. Thanks!


Stephanie Suesan Smith August 4, 2010 at 7:16 am

Well, it is coming up on the time to get seeds in the ground, so maybe you can try a small plot this year.


Leather Dining Chairs August 4, 2010 at 4:54 am

We used to grow them at school too however I’ve always suffered from a bad stomach after eating them, even though I love them! It’s only pickled onions I can stomach


Stephanie Suesan Smith August 4, 2010 at 7:17 am

Bummer. I can’t imagine being allergic to onions. Watch out for leeks and garlic, too, then.


Emma August 6, 2010 at 5:46 am

Thanks for sharing these tips. Since last week we are proud owners of a tiny but wonderful garden and I am gathering information about things I could plant. Onions are a great idea…I absolutely love onion soup and Zwiebelkuchen, a German onion cake made with a lot of onions.


Kent from Bulk Powder January 27, 2011 at 3:05 am

I love onions since it has lots of uses. Aside from onion soup, it can also be use to cure certain illnesses. In our place, we can plant onions the whole year round because of the tropical weather that we have. We might have different ways on how to grow onions but your tips would be a great help in improving our crops. Thanks a lot for sharing this out. Keep going!


Time share February 1, 2011 at 3:32 am

It taste so delicious if there’s onion in the food we serve. It give a smell that I can’t resist to eat more. Good to know that it carries vitamin C and serves as medicine to some illness. Thanks for sharing this article it will help a lot.


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