How to Plant and Grow Onion Sets or Bulbs

Onions are one of those crops that every woman should grow in her vegetable garden. Provided that she and her family like onions, of course! It’s not difficult to learn how to plant and grow onion sets. In my mind, they’re one of the easiest crops there is.

Here’s how to plant and grow onion sets or bulbs for the family table.

How to Plant and Grow Onions

Like all vegetables, home grown, all purpose onions are far more potent than anything you’ll grab at your local supermarket. Flavors are fuller, flesh is crisper and potency level are higher.

Onions are a must in my vegetable garden. It seems I can never grow enough. If you love and use onions as often as I do, raising your own is a wonderful way to take advantage of the best things onions have to offer!

3 Ways to Grow Onions

There are 3 ways gardeners grow onions in their garden.

1. From seed: onion seeds take anywhere from 100-120 days to mature. In many climates, this means you must start them indoors 2-3 months before the planting date in your area.
2. From starts: your local greenhouse center likely sells 3-4 month old onion seedlings in groupings. To plant, you must to separate the wisps and plant each one individually.
3. From sets: whether you grow your own sets/bulbs or buy them from a seed company, onion sets are easy to handle and plant.

Personally I prefer to plant onion sets.

Starting onion from seed indoors can be a hassle. Transplanting seedlings from the local greenhouse center can be a tedious task. Onion sets are easy to handle and once they take off, the starts are hardy and tough.

What’s not to love about that?!

2 Types of Globe Onions You Can Grow from Sets

The onion family is very broad. Do some research and you’ll find there are bunching onions, multiplier onions, tender green scallions, shallots, leeks, chives and many other members to be reckoned with.

But onions most gardeners grow from sets or bulbs typically fall into 2 different categories: sweet onions and storage onions.

Sweet Onions

1. Also known as spring/summer onions
2. Have mild flavor with higher water content
3. Are often consumed raw in homemade salsa and on sandwiches
4. Can be tasty when caramelized or roasted on the barbecue
5. Are not good keepers and generally need to be used within 2-3 months of harvesting

Storage Onions

1. Also known as fall/winter onions
2. Have strong, pungent flavors and lower water content
3. Aren’t usually consumed raw because of their powerful flavor
4. Are tasty when added to meats, sauces and give a real kick to homemade salsa
5. Storage/winter onions are excellent keepers and can last for 6 months+ if properly stored

I grow both varieties in my gardens, with a stronger inclination toward the storage onion, because I like bold flavors. And I like eating my home-grown food throughout the winter months. Winter onions belong in my kitchen. Enough said?

Long Day, Intermediate and Short Day Onions

Apart from onion varieties, gardeners should also know the difference between long day onions, intermediate and short day onions.

Long Day Onions: long day onions are best suited to growers who live in northern climates. These varieties need 14-16 hours of daylight for the plant to produce large, mature bulbs. If long day onions are grow in the south, they’ll produce green tops…and not much else.

Intermediate Onions: intermediate onion varieties grow well in the central USA and need 12-14 hours of daylight for plants to form bulbs. You can (usually) grow long day onions in the intermediate zone as well.

Short Day Onions: short day onions do well in warm, balmy southern climates and can be grown during the cool season. These varieties only need 10-12 hours of daylight for the plant to form bulbs. Try growing short day onions in a northern climate and they’ll create bulbs very early in the year (and have a distinct dislike of cold spring weather).

To discover whether you should grow long day, intermediate or short day onions, take a peek at these maps from Johnny’s Seed. They’ll tell you all you need to know!

Where Can I Buy Onion Sets?

Onion sets aren’t difficult to source if you plan ahead. Most seed companies have sections in their seed catalog dedicated to garlic, shallots, onion and potato sets.

The catch is, you need to place your order before planting day, preferably at the beginning of the year. This ensure the company has stock available to fill your order.

If it’s too late for that, you can check at your local garden or greenhouse center. Many places carry boxed onion sets in early spring. You may not be able to get the varieties you want, but it’s better than an onion-less garden!

When Should I Plant Onion Sets?

In milder climates, gardeners plant onion sets in the fall (much like garlic) and cover with a hearty layer of mulch to keep bulbs from freezing.

But most gardeners plant onion set in early spring, 2-3 weeks before their last average frost of the year. These little bulbs are cold hardy and can withstand a bit of chill!

This being said, you can plant onion sets anytime from early spring-mid summer! Of course, the later you plant, the smaller your onions will be at harvest time. But even if you’re “late” on your planting, they’ll still taste amazing.

How to Plant and Grow Onion Sets

Onion sets are probably the easiest thing to plant in the vegetable garden. I mean it! Even little hands can help with this task, it’s so simple and onion sets are so easy to handle.

Step 1: Mulch the Soil

Do you want to cut back on the amount of weeding and watering you have to do in the onion patch?

Mulch your garden beds with 2-3 inches of rotting straw or hay before planting!

Because here’s the thing: onion don’t develop full, leafy foliage like carrots, squash or beets. Without leafy tops to block the sunlight and keep weed seeds from germinating, the onion bed can quickly become a weedy nightmare!

Old straw bales or decomposed hay makes an excellent soil cover that you can plant onion sets into.

But one word of warning? Only use rotting straw or hay for this task. Bright, fresh bales contain seed heads and if used, you’ll have wheat (or grass) sprouting all over your onion bed.

Ask a local farmer if they have “junk” bales on hand. Old is good. Moldy is better. Rotten is best.

Apply a hearty layer of mulch over the top of your entire onion bed/s before planting to save yourself hours of weeding later on. Oh, and be sure to wear a mask to protect your lungs while you do this!

Step 2: Part the Mulch for Planting

When you’re ready to plant your onion bed, you need to plant into the actual soil. This means you must part the straw and create what I call “growing rows.”

Like this.

These rows should be spaced approx 8 inches apart and about 2 inches of bare soil should be revealed in the bottom of each row.

Step 3: How to Plant Onion Sets

Onion sets shouldn’t be planted too deep, or you’ll restrict the growth of the bulb itself. As a general rule of thumb, these are the directions on how to plant onion sets.

• Use your fingers to create a 1.5-2 inch deep hole.

• Plant onion sets with the pointed side up and the rounded root side down.
  

• Space sets 8 inches apart in each row, unless directly otherwise for your variety.

• Cover with no more than an inch of soil.

• Wait and watch
  

Step 4: How to Care for Onion Sets

If you mulch your garden bed, there should be very little maintenance required to grow large, robust onions.

Because you started onions from sets, they’re properly spaced and won’t need thinning. Mulch should suppress all but the toughest of weeds. And your biggest concern will be watering your onions.

But even there, you won’t have much to worry about. Don’t let the plants dry out when they are young and keep the soil moist underneath all that mulch.

As your onion bulbs mature, you can water less and be none the worse for it.

Step 5: When to Harvest Onions

Onions can be harvested at any time, at any size throughout the summer. I go by a “pull as needed” policy for my kitchen!

But when it comes to harvesting onions for storage, there is a “right” time to harvest.

If you live in a climate with a long, beautiful autumn season, your onions will tell you when they’ve finished growing! Their tops will turn yellow, weaken and eventually fall over. This is a sure sign that the plant is ready to be pulled.

Should you live in a cooler climate where early frosts may threaten your onions, you’ll want to bend the tops over approx 3 weeks before your first average frost date of autumn. This prepares the root for storage and gives the tops time to dry out.

Pull before your first frost of fall and cure onions for a longer shelf life.

Step 6: How to Cure Onions for Storage

When you harvest your onions, leave the tops intact. Handle the bulbs gently to avoid bruising. Bruises will cause decay to settle in much, much sooner.

Pulled onions should be spread out in a dry, well ventilated place. This gives the papery outsides and tops a chance to “dehydrate” and lose moisture.

They are ready for storage when the outside 2-3 bulb layers are papery and the tops are brown and dry.

Step 7: Best Storing Practices for Onions

Onions like cool, dry environments with good air circulation. Their storage container should contribute to this as well. Baskets, mesh bags, crates or even open boxes make excellent storage containers.

And keeping your onion harvest in complete darkness will discourage sprouting.

Sweet onions won’t keep long, so use them up first. Your winter onions (if you grow the right varieties and have proper storage conditions) will keep until spring.

Pick through your onions often and dispose of any that may be turning bad. One bad apple…err onion….spoils the batch!

That’s How You Plant Onions

Once again, I want to reiterate just how simple it is to grow your own onions. Whether you want a year’s supply of home grown onions, if you’re a real food cook or just a mama who wants to delve deeper into making her own home remedies, onions have always had a place in the kitchen and natural medicine cabinet!

And I hope you’ll take up growing your own this year!

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