How to Plant Onions

In today’s tutorial, I’ll show you how to plant onions from starts or seedlings. Recently I decided to go ahead and get my onions out in the ground. I might be a little early, (this is late Feb early March) but we’re going to play it by ear and see. I think I’ll be okay.

There are 3 methods for planting onions.

  • Sets
  • Seeds
  • Seedlings or starts or plants – (what we will discuss today)

Onions can be grown in three different ways, or you can start onions in three different ways.

  • start onions from sets, which is basically the little onion bulb
  • you can plant onions from seeds
  • you can plant onions from seedlings or plants.

Today I’ll show you how to plant onions from seedlings or starts.

How to Plant Onions from Seedlings

I personally like to grow from either seedlings or seeds themselves. I often like to start the seeds but this year I am going with the seedlings or the starts which are basically baby onion plants that have been started for you.

Sharon's garden gloved hand holding onion seedlings or starts.

We just moved to Tennessee. This is our first year in this garden, my greenhouse is not completed, and I simply don’t have a real good place to start seeds.

Types of Onions – Long-day and Short-day varieties.

Okay. Let’s talk about the type of onion that you’re going to want to plant.

The growth of an onion is dependent upon the length of day or dependent on how much daylight it is getting. Of course, they like a bright, sunny location with loose soil, evenly, moist. Practically every plant likes those conditions.

If you draw a line across the country, east-west, just above Tennessee, heading horizontally across the country. There’s some up and down but this is approximate.

If you live north of that line, you’re going to choose a long day onion. If you live south of that line, you want to choose a short day onion.

There are also some varieties that are considered intermediate, and you could go either way with those, keeping close to the center line. These areas are divided by the length of the day in your growing season.

I’m in Tennessee. I’m just below the short day/long day line. And so I am doing short day onions and an intermediate day onion.

How do you know if you have a short day or long day onions?

It should say on the tag of whatever onions you buy or on the seed packet, or the package of bulbs.

It doesn’t matter which type of growing you choose, look for the short day and the long day. Then you’ll have better luck depending on where you live.

Planting Onion Seedlings

Let me show you my little garden bed here. This is where I planted my red onions, I basically have three rows. There’s a row here, and there’s a row here, and there’s a row here. I also planted some yellow onions and they’re over on the other side of my raised bed.

This raised bed is a new bed to me and I love it so far. (Haha, This is the beginning of spring. How can I already know that I love it? But I do.) Onions do well in soil that is worked up nice and loose. Even if you are a no-till person, make sure that the soil is not hard and compact. Hard clay would not work well. You’re going to need to amend it.

Added Tip for those with clay soil –

If you do have less than perfect soil you still can grow onions. Just be sure and plant very shallow so the soil doesn’t inhibit the growth of the bulb. And you’ll need to keep it moist but not sitting in water. A good mulch will be important for you.

I planted fairly close. If you do some research and try to look for how far apart to plant your onions, I’ve seen anywhere from three to six inches. All I did was spread my fingers apart to do my measurements. I didn’t take a ruler out and lay it out. I just went about the width of my fingers, and I would say it’s probably three and a half, four inches apart.

Sharon hand with fingers spread to show how far apart to plant the onion starts.

The distance between my outside row here, to my outside row over here, is about 12 inches.

When I got that completed, to the point where I wanted to stop, I still had onions left, so I went ahead and I planted a row down the middle. So that makes my rows about six inches apart. It’s fairly close. I think it’s going to be fine depending on how big the onions get.

Now, as I said, this is my first year in Tennessee, and so we’ll see if they get a lot bigger than what I’m used to. But when I look at how this is laid out, and I metally picture how big onion would get, for me, I think I’m good. They’re going to have room enough to grow.

Hand holding 2 tiny onion starts.
Sometimes onion starts are super tiny! Plant them anyway, they’ll grow.

Thinning Onion Seedlings

My plan is if I just have really good luck and it starts getting crowded, I’m just going to thin them and use them in the kitchen. I’ll just pull out every other one as they’re getting bigger and leave the others to have that more space to grow. I don’t think it’s a big deal.

Planting Onions in a Raised Bed Garden

This is a raised bed garden, and from what I understand, you can plant things pretty compactly in a raised bed just because it’s got so much depth to it and the soil is looser.

Square Foot Gardening Book.

This is what I did. Time will tell. I will do a post update probably later when I’m harvesting.

(Harvest update– The spacing on my onions was just fine. They did not get crowded. I did a video here of the onion harvest I got with this patch.

Tips – quick easy measuring sticks.

This is just a piece of scrap wood, and all I did was, I took a Sharpie marker, and I marked every six inches across, just as a planting guide. All I have to do is just lay that out there, and I know from there to there is 12 inches. I’ll just leave this in my garden all year. It’s just a nice way to have those measurements without having to bring a ruler out or something like that. Of course, you can just eyeball it.

One thing I did also when I made my row … I’m not real good at making straight lines. I did it with my hoe. Figured out where I wanted my row. I just used this to make a line, and then I just planted all along where that line is. That’s just an easy way to do it. I started at one end and planted it. I spread my fingers apart, planted the next one, spread my fingers apart, and planted the next one.

Raised garden bed with indentations showing how Sharon marked the rows with her hoe.

How Deep to Plant your Onions

Onions do not need to be planted deeply. An inch or two is all that is needed. Get the roots in the ground and part of the bulb area. All I’m doing is taking and just doing a finger width apart. I just poke a little hole. Stick that down in there and pinch it. Then I make my next hole. Stick that down in there and pinch it. It is a light pinch. If you have heavy clay soil planting shallow is especially important. The heavy dirt can inhibit bulb growth if you go too deep.

You don’t want to plant real deep. You just want to get the bulb in the dirt. Don’t come up clear up on the stem. Onions do not need to be planted deep. That is as simple as it needs to be.

That’s it. We’ll see how it goes. I’m excited. Time will tell.

Onion starts planted in a row.

That’s it. Planting onion seedlings is a great way to get onions in the ground.

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how to plant onions

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