Winter Sowing: Your Guide to Growing Seeds in Cold Weather

Did you know winter sowing can make plants healthier and stronger? Surprisingly, winter weather provides the perfect conditions for starting flowers, herbs, and vegetable seeds.

Inspired by one of our videos about the 7 crops you can grow with snow on the ground, this post is especially written with northern gardeners in mind. But early season gardening is something we advocate everyone tries because it is a great way to increase yields and extend the growing season!

Using this hassle-free, easy method is a great way to start your garden early without expensive indoor setups. This guide will show you the benefits of winter sowing, how to winter sow seed, when to sow, and which crops to choose for success.

Let’s grow bigger together!

Why I Love Winter Sowing

Whether gardening in raised beds, container gardening, or in-ground gardening, starting a garden each spring might be the most challenging part. I love winter sowing because it uses nature to simplify the process.

Unlike starting seeds indoors, which requires a dedicated space or grow room complete with grow lights, reusable starting containers, and seed-starting heating mats, winter sowing is done in your outdoor gardening space with very little equipment.

What is Winter Sowing

Winter sowing is a hands-off technique for starting seeds outside in cold winter weather. Similar to cold stratification, both expose seeds to cold temperatures to break dormancy and soften the seed coat.

Winter sowing seeds mimics when seeds naturally fall to the soil during the prior season and sit dormant until germination. It is vital for certain types of seeds that can germinate only after a period of cold weather, like a start-up sequence. 

The Benefits of Winter Sowing

I’ve done winter sowing many times with great success. Winter sowing lets me start my garden early, even with snow still on the ground or in the forecast.

In short, winter sowing is great for saving money and growing strong plants. It's a smart and green way to garden.

When to Start Winter Sowing

Finding the best time for winter sowing depends on your weather and USDA growing zone. Here in Michigan, I plant my winter-sown seeds in January.

The timing doesn’t have to be exact, but this chart should give you an idea of when it is a good time to winter sow in your area.

What Crops Can Be Winter Sown

I’ve seen people winter sow just about anything, even tomatoes and peppers. Popular choices for winter sowing include flowers, herbs, and brassicas.

For starters, I recommend trying these seeds for winter sowing:

• Spinach

• Peas

• Brussels Sprouts

• Lettuce

• Radishes

• Beets

• Cabbage

• Kale

• Broccoli

• Cauliflower

• Poppies

• Snapdragons

• Purslane

• Thyme

• Cilantro

• Oregano

• Tarragon

How to Winter Sow

We are going to turn an empty milk jug into a mini greenhouse that will sit outside in winter weather. The milk jug will protect the seeds from being eaten by mice and birds while keeping the soil warmer.

When the weather starts to warm up, the seeds will germinate faster than if they were direct sown into the garden. It's really cool.

Materials Needed for Winter Sowing

• Seeds - Select seeds from the list above or others that benefit from cold stratification.

• Plastic Milk Jugs - Collect empty milk or water jugs or other similar containers. Clean and save them until you are ready to winter sow.

• Scissors - You will need scissors to cut the jug in half and poke holes in it.

• Garden Marker - All markers are not created equal! Use a garden marker that is fast-drying, waterproof, and UV resistant.

• Soil - I use fresh compost or soil straight from my garden, but you could also use a seed starting mix or even potting soil, whatever you have on hand.

Step-By-Step Instructions

1. Use the scissors to poke small drainage holes in the bottom of the milk jug. About 12 to 16 small holes evenly spaced apart should allow adequate drainage. Pro-Tip: The drainage holes are critical. They will prevent the seeds from rotting. You want the soil damp but you do not want water sitting in the jug for long periods of time.

2. In the middle of the height of the milk jug, cut the milk jug in half horizontally. Keep the top and bottom because both halves will be used.

3. Remove the cap from the top of the milk jug and throw it away. Pro-Tip: Leave the cap off! This allows rain and snow to fall into the milk jug, which irrigates the soil and keeps it moist. Unless you have a very dry winter, you will not need to water these jugs.

4. Fill the bottom of the container about ¾ full of fresh sifted compost or soil of your choice.

5. Grab a seed packet and sow seeds in the milk jug, not worrying about the density. Cover the seeds with a thin layer of compost if necessary.

6. Moisten the soil with a little bit of water until lightly damp.

7. Put the top of the milk jug on the bottom so that it slides inside the bottom down to the soil level. Make sure that the top is inside the bottom far enough that the bottom part pushes in to hold the lid securely in place. Some people use duct tape to reattach the top of the jug, but it is not necessary.

8. Using a garden marker, label the outside of the jug with the type of seeds sown inside so you don’t forget what is growing. I also like to add the date planted.

9. Place the jug outside in your gardening area and wait until the seeds start to sprout. They will sprout when the weather is right for them.

10. When the seeds have sprouted and reached a height of 1 to 2 inches, remove the top from the jug.

11. At this point, you can spoon transplant seedlings directly into the garden. You don’t have to worry about hardening off the seedlings or moving them into other pots.

And that's it! It's pretty simple to winter sow crops and I love that it eliminates the steps of having to start seedlings indoors, pot them up, if needed, and then harden them off prior to planting them in the garden. 

Grow bigger!