Starting Onions from Seed

Photo Credit
Celeste Longacre
Celeste Longacre

I love onions. They are great for bringing out the flavor of meats. Now is the time to plant onions if you are going to grow them from seed. Here's how.

It’s wonderful to grow a real “keeper” that will last well into next summer. Check your gardening catalogues to see which onion varieties are recommended.

Planting Onions From Seed

Fill a flat 2/3 with potting soil. Add a bit of kelp meal for additional minerals and dig this in.

Broadcast the onions seeds all over the top of the soil. Cover with ¼ inch of new dirt. Even though the onions will be crowded while they live in the flat, they don’t seem to mind.

When the onions come up, they look like blades of grass.

They will continue to grow becoming quite long. Cut them back to four inches when they get longer than that.

Place them in a sunny window but don’t give them any extra light at night. Many onions are day-length sensitive. This means that they put all of their energy into growing greens while the days are getting longer. As soon as the days begin getting shorter, they form their bulbs.

Keep them warm until the weather outside has softened.

How to use them?  Why, onions add flavor to every meal. I put them in stir-fries, include them when cooking a pot roast or chicken, and add them to all my bone broth stocks.

See the Almanac's Onion Growing Guide for more information about planting, growing, harvesting, and storing onions.

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Sunny T (not verified)

1 year 9 months ago

Celeste when you refer to sunning the onions for 7 days are you meaning to hardening them off? Getting used to the weather outside.

Suzan Hill (not verified)

6 years 8 months ago

Okay, once the weather is conducive and I have this "lawn" of onions in my flat, how is it best to transplant them without killing off the little tender things?

Hi Suzan,

You can transplant them by gently pulling them apart and placing them in a hole created with a sharp stick or dibble.

Laurie Thorpe (not verified)

6 years 8 months ago

What is a good onion to grow that will store well? Mine always end up rotting from the inside out. thanks

Hi Laurie,

Copras store quite well. Of course, you have to get them ready by sunning them for 7 sunny days (bringing them in at night).