A Guide to Winter Sowing {Starting Seeds in Winter}

Winter sowing involves sowing the seeds outdoors in miniature greenhouses during the winter, allowing them to germinate naturally in spring.

A drawing of seeds planted in a milk jug.

Results of a recent social media poll showed that 96% of people who start their plants from seed do so by following the instructions on the back of the packet. They sow seeds in pots in sunny windows 6-8 weeks before the last frost. It makes sense that you would follow the directions, but what if there were an easier and much better way to get those seedlings started?

This guide to winter sowing is like a backstage pass to the magic of gardeningβ€”skip the usual routine and embrace a simpler, more effective way to kickstart your seedlings. With its miniature greenhouses and natural germination, winter sowing adds a touch of homestead wisdom to your gardening journey. Whether you’re a first-time veggie gardener or a seasoned pro, the ease of this method is a game-changer. Grab those milk jugs, make some DIY greenhouses, and let your seeds enjoy a winter wonderland until spring bursts forth. Your future garden will thank you for this stress-free start!

What is Winter Sowing?

The idea behind winter sowing is that you sow the seeds outdoors in miniature greenhouses during the winter, allowing them to germinate naturally during the spring. If you live in a northern climate and have snow, this method works even better because the melt adds all the moisture your seeds need. An added bonus to winter sowing over traditional methods: No period of hardening off plants! My biggest downfalls in seedlings are forgetting to water them or over-watering them and then forgetting to bring them in at night when I’m hardening off the plants. This method is perfect for me.

How to Sow Seeds in Winter

So, how does one winter sow? Easily!  You need a plastic container to put your seeds in. Some things that work well are large plastic jugs (like the ones pretzels come in), 2-liter soda bottles, or clear plastic take-out containers. It will work as long as it will hold 3-4 inches of soil.

My personal favorite is to use milk jugs.  With their shape, you can squeeze a bunch together, and if you save caps/lids, you can regulate watering during heavy spring rains. I will show you how to use a milk jug, but the same rules apply to other containers. First, you need to put drainage holes in the bottom and sides. Being somewhat OCD, I like to do three holes, shaped like a triangle, in each of the four “sections” of the bottom. You also want to place three or four holes about 1/4 – 1/2″ up on the sides. I use the transition of textured plastic to smooth plastic as a guide. There is no set rule for the hole size, but I used a 1/8th drill bit.

Tip: Before drilling holes, fill your container with water and pop it in the freezer or outside until it’s frozen solid. This prevents your container from collapsing when you push the drill bit against it.

After you have all your drain holes in place, you need to make a hinged lid. I used the bottom of my handle as a guide, but with any container, you want your lid to be high enough to allow for 3-4″ of soil. Using a sharp knife and plenty of safety measures, cut across the container, leaving about an inch uncut. This will create a hinge.

My milk jug transformed into a winter sowing greenhouse.

Planting in Your Milk Jug

Once you have your greenhouse made, all you do is prepare the soil and seeds. Add your soil and wet it well. Let it drain out the holes you made until the soil is damp but not soaked. Add your seeds according to the packet as far as depth and spacing (though I fudge the spacing and have typically done okay). When you are done, just duct tape the lid closed, remove the cap, and label the outside of the carton with the plant name. If you are using a container that doesn’t have a cap, make sure to put some holes in the top so rain and snow can enter the container.

Placing Your Mini Greenhouses

Once you have everything planted, it’s time to put on your snow boots and jacket to get your greenhouses to their proper place outdoors. The only considerations for placement are that you want your containers to get rain, so don’t put them where they’re under an overhang, and they will need sunlight come spring, so if you can place them in a sunny place now, you won’t have to move them later. I put them right smack in the middle of the front yard.

Because the milk cartons are white, they hardly show up, and after a snow, no one will know they are there. On that note, if you have small children, you may want to mark the area somehow so no one crushes your greenhouses while building a snowman.

When to Start Your Seeds in Maine

This schedule is based on my Maine growing zone, 5b.

January

  • Perennial Flowers
  • Hardy Annual Flowers
  • Brussels Sprouts

February

  • Spinach
  • Kale
  • Peas
  • Broccoli
  • Thyme
  • Sage
  • Oregano
  • Cilantro

March

  • Lettuce
  • Carrots
  • Basil
  • Parsley
  • Bok Choy
  • Beets

April

  • Tomatoes
  • Onions
  • Peppers

Click Here for zone-specific winter sow planting schedules.

Winter Gardening for Beginners by Lindsey Pylarinos
The Winter Harvest Handbook by Eliot Coleman
The Year-Round Vegetable Gardener by Niki Jabbour

See more milk jug upcycling ideas here, and don’t miss one of our most popular upcycling posts, 22 New Uses for Old Pill Bottles.

Frequently Asked Questions

While winter snow and rain contribute moisture, especially in northern climates, monitoring soil moisture is essential. Water the seeds initially and ensure the soil stays damp but not soaked. In periods of low precipitation, supplemental watering may be necessary.

Winter sowing benefits colder climates, especially when snowfall provides natural moisture. However, it can also be adapted to milder climates with adjustments to planting times and consideration of local weather patterns.

Placing the mini greenhouses in a location that receives rain and sunlight is ideal. However, during severe weather, you can provide additional protection by placing them in a sheltered area or covering them temporarily.

If you’ve found value in this blog post and enjoyed reading it, why not share it with your Pinterest community? Pin the image below and spread the love!

A Pinterest-friendly graphic for winter sowing your seeds.

So what are you waiting for? Don’t wait for the last frost. Don’t spend hours counting backward. Throw some seeds in milk cartons and toss them out in the yard. You’ll thank me in the spring.

Have you tried winter sowing in your garden? Share your favorite plants to winter sow or any tips you’ve discovered along the way. If you’re new to this method, what seeds are you excited to try? Let’s swap stories and seed-sowing wisdom in the comments below!

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165 Comments

  1. I would love to use this article as a link. We are homeschoolers, and are trying this method for our gardening unit. Pretty please, may we link?

    1. Jessica Lane says:

      Absolutely! Thank you so much Jodie πŸ™‚

  2. laura mccubbin says:

    Love this idea! Question, do you keep the cap on or off?

    1. Jessica Lane says:

      Cap off so the rain can water them πŸ™‚

      1. laura mccubbin says:

        thanks! I have a ton of these jugs,so I’ll be busy making these this week!

  3. Great idea, thanks! I do have one question. Do you lift the lids on warm days, or leave them taped shut until you’re ready to transplant?

    1. Jessica Lane says:

      I leave them taped up until I’m ready to put them in the ground, but I do move them in the shade if they seem to be getting a bit toasty.

  4. Teresa Snyder says:

    I used my hot glue gun without any glue to melt the holes in the milk jugs. Worked like a charm!

    1. Jessica Lane says:

      That’s a great way to get holes in your carton without hurting yourself. Thanks for sharing!

  5. What a good idea! My seeds normally get killed off because of the cold whether and nothing germinates. Thanks.

    1. Jessica Lane says:

      You are so welcome!

  6. I live in montana and one day the weather is 60 then is 20 below. My question is : wouldn’t the constant warm and cold trigger germination? Also second question. Can you use these for sweet peppers that need to be in Soil that is 75-80 degrees? Thank you.

    1. Jessica Lane says:

      Your best bet would be to wait until close to spring, but winter sowing should give you a bit of a head start and you won’t have to worry about hardening them off.

  7. I saw you’re a Maine girl, I am too! πŸ™‚ Shared this on my facebook page.

    1. Jessica Lane says:

      Welcome Mainer friend! And thanks for sharing πŸ™‚

      1. Shayne Zarkowsky says:

        I am too! Cant wait to try this! So excited to see we can do this here. I want to garden economically and it doesnt get much better than this!

    2. Shayne Zarkowsky says:

      I am too! Cant wait to try this!

  8. I am not sure that planting in plastic is safe because of the leaching out of the chemicals. I usually start my plants in peat pots. Do you have any information on this subject?

  9. I assume that the milk jugs need to be the clear (soda type), or semi transparent sort (water type), not the white ones (milk type), correct?

    1. Jessica Lane says:

      As long as it isn’t opaque, you should be find. You are correct, though, that those light-block bottles won’t work.

      1. So we cannot use the regular milk jugs then? They need to be mostly clear? Also so the seed just freezes in the wet soil and then in when it starts to warm up, it thaws like the ground outside does?

        1. Jessica Lane says:

          Correct and correct. Light block bottles won’t work since they do just that, block light. Standard “milky” milk bottles work just fine though. As far as the seeds freezing, that’s okay. The idea behind this method is that the seeds take their cue from nature and begin sprouting when nature says it’s time. They start sooner than they would normally because your container heats up like a mini greenhouse.

  10. LOVE the idea!! Will work excellent here in cold Norway. πŸ™‚

    1. I don’t know much about gardening in Norway, but cold and snow are no problem with this method. Make sure you swing by on Thursday when I talk about how to winter sow for the various gardening zones. I’m not sure if yours work the same way or if they are a US thing, but it should give you some direction.

  11. The easy way to make holes in plastic is poking it with hot soldering iron. That’s what I do anyway.

    1. Why did I never think of that. Great idea!

      1. Or the tip of a hot glue gun.

  12. narel hebb says:

    how many seeds do you, put in the milk jug and what time of the year would I plant, we live in Thomas,Wv

  13. I was wondering how difficult it is to transfer The plants from the container into the garden without damaging them? Have you ever tried peat cups to plant in?

  14. How many seeds per milk jug? Do I use the whole packet?

  15. <3 this idea!! I've decided this year to just grow heirloom veggies so I can save the seeds and know there are no GMO addititves. I plan on getting the containers I've been saving for cloches and use them now to start my seeds. What a wonderful site! Thanks for sharing and answering all our questions. πŸ™‚

  16. I really think im gonna give this a try. Sure would take alot of stress off of me! Thank you! Sooo glad i found you

  17. I really think im gonna give this a try. Sure would take alot of stress off of me! Thank you! Sooo glad i found you

  18. Erin Schmidt says:

    This will help so much as I have cats that eat all my seedlings that I start inside. I love that you dont have to harden the plants. I also deal with high winds most of the time. Going to have to get creative on how to keep them from blowing away. I need to look up my zone. Central KS. Ill be checking back on Thursday! Thanks!

    1. Cats and small children are the reason I was instantly drawn to this method.

    2. I would put some rocks in the bottom of the milk cartons, and then the soil, to help keep them stable in the wind!

  19. Stephanie says:

    What kind of soil do you use? Do you purchase a bag from the store? My ground is too frozen to dig anything!
    I’m excited to try this!

    1. I buy starting soil from Home Depot. I keep planning to store soil from my garden and creating my own mix, but I haven’t done it yet.

  20. Want to try this but live in southwest New Mexico. Any ideas on my zone.

    1. I’ve gotten a lot of questions regarding zone-specific guidelines. I am going to address all of that on Thursday, so be sure to check back.

  21. What about super cold nights? In February, we normally have a few 20 below zero or colder nights – won’t this kill the seeds before they can germinate?

    1. They are protected in their little greenhouse. Before they begin germinating (which is triggered naturally by the warming weather), they are dormant, so no harm will come to them.

  22. I live in Northern BC zone 2b . I am wondering if we can do this here as well. Our winters are pretty cold and smow is usually gone by May. We usually don’t plant until Mid May.

    1. I’ve gotten a lot of questions regarding zone-specific guidelines. I am going to address all of that on Thursday, so be sure to check back.

  23. you never really explain what to do with the lids. could you please elaborate?

    1. Sorry I didn’t elaborate. You remove the caps to allow for the rain and snow to water the soil inside.

  24. Last Fall, I made a hoop tunnel garden (3′ x 15′ x 20’+). What would you suggest for planting seeds in this?

    Last season, I had volunteer tomato plants in my garden, that sprouted the same time I was planting purchased plants from dealers. Both plants produced tomatoes at the same time, making me wonder why I spent $$$ on the larger plants. This year, I will plant more interesting tomato seeds. I am so looking foward to planting your way. Thanx much!

    1. You can certainly start plants and seeds earlier when you use a plastic hoop setup. Not knowing the specifics of your growing area, I can’t tell you for sure when a good time to start would be. I would suggest sticking a thermometer in the covered area and tracking the temperatures for a bit.

      1. Liz Davey says:

        I have been doing this for years and it does work well. You can skip the ice and drill if you use an ice pick or awl to make the holes in the top and bottom of your jug. I have also used 1/2 gallon oned, but did not have good luck with quart size as they tip over too easily.

        1. Jessica Lane says:

          Great tips Liz! Thanks so much for sharing.

  25. I live in central Mississippi, zone 7 I think. Would like more info. on Winter Sow planting for my area, especially what can be planted and when. Thanks.

    1. I’ve gotten a lot of questions regarding zone-specific guidelines. I am going to address all of that on Thursday, so be sure to check back.