Winter Planting Onion Seed – Super Easy!

winter planting onion seed

Winter Planting Onion Seed – Super Easy!

winter planting onion seed

A couple years ago, I tried this seed sowing method for my onions and it worked really well, so I’m going to give a quick tutorial. It’s very easy and low-maintenance, and I am all about creating less work for myself. So here is my method for winter planting onion seed for harvesting next summer.

Why I Love to Grow Onions

Onions are a great item to grow because they tolerate the cold really well, which is a big plus here in Northeast Ohio. It’s December as I write this and I still have some green onions growing out in the garden that I could go pull today for dinner. And the larger types like Walla Walla will keep in cold storage for a pretty long time. I can plant a bunch of onion seed for a few dollars and have onions for months and months. They are almost as easy and productive as garlic, which is my absolute favorite and easiest edible plant to grow.

I also prefer to grow onions from seed because planting from seed is more economical than buying plants. Plus it creates less waste (no garden center plastic cell packs), and you have access to a greater number of plant varieties using seed than you can usually find when you buy plants at a garden center.

What You Need

You could just sow your onion seed on the ground in whatever spot you intend to grow your onions next year, but as any gardener knows, digging critters will ruin many garden beds between now and spring and delicate seedlings like onions don’t survive. (We have an insane number of squirrels in our neighborhood and they ruin anything I try to grow from seed if it’s uncovered.)

I find the easiest thing to do is use a plant tray with a clear cover or a covered pot. Takeout containers work well too. I had a couple leftover takeout containers from rotisserie chickens, and thought they were perfect for reusing as mini plant greenhouses. I have cleaned them thoroughly.

Potting soil, onion seed and takeout containers

I have used regular takeout containers in the past, but these I have now are deeper to allow more root space and will allow more head room as the onions begin to sprout, so they are perfect. You want some type of clear lid to allow the sun in, and if the lids aren’t vented, you should poke a few holes in it to allow some air flow. I like to also poke a few holes in the bottom tray as well, so that it can drain and doesn’t get too waterlogged after a rain.

Aside from the containers, all you need is some good potting soil and your seed. Need some onion seed? I like Park Seed, they have good quality seed. (I don’t make any commission from this company, I just like their selection and quality.)

Planting Onion Seed in Winter

The beauty of planting onion seed this way is that it works with natural cycles and allows the seed to sprout at the proper time and get used to outdoor conditions right from the beginning. So there’s no guesswork about when to plant and no challenging hardening off process when you start seedlings indoors and have to gradually acclimate them to the outdoors.

It’s December here in Ohio, so this is a good time to get my seed planted. I have also done it later, in January and that works fine as well. I wouldn’t start it too early, because the seed might start sprouting immediately. The strategy is to plant when it is quite cold and the seed will naturally sprout when the time is right.

I am doing two different types of onions today, green onions and Walla Walla. I have labeled the trays with some masking tape and a permanent marker. In previous years I made the mistake of labelling the lids, and then a big storm or an animal knocked off the lids and then I didn’t know what was what. So this year I am labelling the trays.

I put some good potting soil in each tray and then follow the depth instructions on the seed packets (in this case, plant seed 1/4 inch deep). Onion seed is really tiny, I just sprinkle a decent amount in there and cover with a thin layer of soil. Then I use the mist setting on my garden hose to water the trays thoroughly and put the covers on.

I like to set them in an area where they will get sunlight but be sheltered from blowing around. We get pretty high winds in the winter here, and they will likely blow over if I just leave them totally exposed. So I snuggle them into my herb garden:

Winter sowing onion seed

The lids on these takeout trays are particularly nice because they snap on good and tight, so I am not too worried about them blowing off, but I could put a big rubber band around them or stake them down if they weren’t secure.

That’s it! You’re done until the weather warms up.

Caring for Your Onion Plants in Spring

Onions will start sprouting pretty early. Once the weather starts to warm above 45-50 degrees F, you should check on your onions and remove the lid on warmer days to allow the seedlings to get some air and not get too warm. If the soil is getting dry, be sure to water it. For cold evenings, put the lid back on. Onions are pretty hardy, so you don’t have to baby them too much but I like them to be covered anytime the temperatures get close to or below freezing. Other than that, just keep them from getting too dry and you’ll be good.

Once the temperatures are safely above freezing in your region and your onions are a few inches tall, you can transplant them to wherever you are going to be growing them for the summer. Just tear them apart in small clumps (it’s impossible to separate each individual plant, don’t try), then plant and water.

That’s pretty much it. I grow a ton of onions this way, and it’s super easy. Give it a try and let me know how it works for you!

One thought on “Winter Planting Onion Seed – Super Easy!

  1. Sounds good. I didn’t know I could plant them this early in Northern Ohio. I’ve always grown them from sets but will try seeds in a plastic container this year.

Leave a Reply

Your email address will not be published. Required fields are marked *