Winter Sowing: How to Grow Flower Seeds Outdoors During the Winter

May 24

January is a time for planning, plotting, and dreaming about the upcoming growing season for us folks in colder growing zones.

But did you know it can be a time of growing, as well?

The past three years, I have been growing cut flowers in my summer garden, and this year I have big plans to extend the garden and grow more varieties. With my expansion plans, I’m also experimenting with different ways of starting flowers from seed.

Through my research and seed-starting methods, I came across the winter sowing method. (Shout-out to fellow gardener, Lindy, at @smalltowngardenlife!) She shared this method last year, and I have been intrigued ever since.

I decided to give it a go myself this year and record the process so you can learn from my experience and try it, too!

What You’ll Learn:

What is Winter Sowing?
What are the Benefits of Winter Sowing?
What Types of Flowers Can Be Grown Using the Winter Sowing Method?
Supplies Needed for Winter Sowing
How to Winter Sow Flower Seeds

What is Winter Sowing?

Winter sowing is a method of seed starting that involves planting seeds in “mini greenhouses” (plastic containers) and placing them outdoors during the winter months. The natural freeze/thaw process, snow, and temperatures spur the flowers to germinate and grow.

What are the Benefits of Winter Sowing?

Get Growing Sooner: For those of us in cooler climates (think hardiness zones 3-7), you can get your seeds planted sooner so you have flowers earlier in the spring. No waiting for the last frost to plant!

Indoor Space Saver: You don’t need a special room or shelves inside your home. The seeds stay outdoors.

No Fancy Materials or Equipment Needed: You are relying on Mother Nature to provide the light and moisture the seeds need to grow so no grow lights are required.

It is Easy: This is a “set it and forget it” method. Once the seeds are planted, you don’t have to do much until it’s time to plant them in the ground outdoors.

Plants Don’t Need Hardened Off: The plants will be acclimated to the outdoors and ready to plant when the time is right. No hauling the seedlings in and out of your house to harden them off prior to planting.

What Types of Flowers Can Be Grown Using the Winter Sowing Method?

Perennials and hardy annuals are the best plants to winter sow.

Perennials are plants that come back year to year. Hardy annuals have to be planted each year but can tolerate cooler temps and a (light) frost.

Some varieties I am winter sowing this year include: Bells of Ireland, Scabiosa, Snapdragons, Forget-Me-Nots, Bachelor’s Buttons, Ammi, and Feverfew.

Basically, think of flowers that can naturally reseed themselves in your garden from year to year.

Supplies Needed for Winter Sowing

Plastic Container: Milk jugs work well! Anything that is clear with the ability to have drainage holes and venting.

Potting Mix: You can use a seed starting mixture, but really any type of soilless potting mix will do.

Seeds: Again, perennials or hardy annuals are ideal.

Labels: Use something sturdy that can hold up to the elements or label the inside of the container with a permanent marker.

Knife or Scissors: Something to cut through the plastic container.

Tape: Duct tape, packing tape…something that will stick to the plastic and hold up to the weather.

How to Winter Sow Flower Seeds

First, use your knife to cut the plastic container in half. I left a bit of the container attached to create a “hinge” effect. If there are no holes in your container, make some so there is appropriate drainage.
Fill the bottom portion of your container with moist potting mix. (I found it is easier to moisten the soil ahead of time than to water after the seeds are planted.)
Plant your seeds at the appropriate depth, and place your label inside the container.
Secure the container closed by taping around the cut portion.
Place your containers outdoors — ideally in a sunny spot where the wind will not tip them over. You’ll also want to ensure they can receive moisture if there is snow or rain. Leave the caps OFF of the container for ventilation.

The containers will stay outside through the winter and early spring months. You don’t need to do a thing other than to make sure they stay upright. As the temperatures rise, your seeds will germinate and grow in their mini-greenhouse. Once the ground is thawed enough to be worked, plant your flowers outdoors and enjoy!