Winter Sowing: The Easy, Budget-Friendly Way to Start Seeds
I tried winter sowing for the first time this year…and I’m hooked!
Winter sowing is an effective and inexpensive method for starting seeds outdoors during the colder months. By utilizing simple materials and allowing nature to guide the germination process, you can enjoy healthy, strong seedlings ready for transplanting in the spring.
What is Winter Sowing?
Winter sowing involves planting seeds in miniature greenhouses made from recycled containers and placing them outside during winter. This technique takes advantage of natural temperature fluctuations to stratify seeds, breaking their dormancy and promoting germination at the appropriate time. It's particularly beneficial for seeds requiring cold stratification, such as many perennials and hardy annuals.
What the Heck is Cold Stratification?
Cold stratification is a natural process that some seeds require to break dormancy and germinate successfully. In the wild, seeds from many perennials, trees, and native plants fall to the ground in autumn and endure the cold, moist conditions of winter. This chilling period helps to soften the seed coat and triggers internal changes that prepare the seed for germination once temperatures rise in spring. Gardeners can replicate this process by exposing seeds to cold and moist conditions, either by sowing them outdoors during winter or by placing them in a damp medium inside a refrigerator for several weeks. This technique ensures that seeds germinate uniformly and at the appropriate time, enhancing the success of your gardening efforts.
Some seeds require cold stratification due to evolutionary adaptations that ensure their survival and successful germination in specific environmental conditions. Cold stratification mimics the natural winter period that certain seeds need to break dormancy. Here's why this process is essential for some seeds and not others.
Why Some Seeds Require Cold Stratification
Seeds from many perennial plants, trees, and native wildflowers have developed dormancy mechanisms to prevent premature germination during unfavorable seasons, such as winter. This dormancy is often physiological, meaning the seed contains internal inhibitors that prevent germination until specific conditions are met. Cold stratification—exposure to cold, moist conditions—breaks down these inhibitors, signaling to the seed that it's safe to germinate. This process ensures that seedlings emerge in spring when the environment is conducive to growth.
Why Some Seeds Do Not Require Cold Stratification
In contrast, many annual plants and cultivated varieties have seeds that lack such dormancy mechanisms. These seeds are often ready to germinate immediately upon exposure to favorable conditions like warmth and moisture. Through domestication and selective breeding, humans have favored plants that germinate quickly and reliably, reducing or eliminating the need for dormancy-breaking processes like cold stratification.
Benefits of Winter Sowing
Cost-Effective: Utilizes recycled materials like milk jugs or plastic containers, reducing the need for expensive seed-starting equipment (trays, grow lights). Bonus - we’re getting a second or third use out of these single-use plastics!
Space-Saving: Seedlings are grown outdoors, freeing up indoor space and eliminating the need for grow lights or heating mats.
Hardier Seedlings: Exposure to natural conditions results in robust plants that are already acclimated to the outdoor environment, minimizing transplant shock. No need for the cumbersome process of hardening off fragile seedlings! They’re naturally hardened off through the winter-sowing process.
Extended Growing Season: Allows eager gardeners to start seeds earlier than traditional methods, leading to an extended harvest period. Also - if you love gardening, you can garden in the winter!
Ease: This is SO easy. No checking your seedlings each day for water. No managing your grow lights. No bringing fragile seedlings outside for 2 hours, 4 hours, 6 hours to acclimate them before they can grow. You’ll need to keep an eye on them once they germinate, but until then, let them be.
Materials Needed
Transparent Containers: Recycled items such as gallon milk jugs (washed well!), gallon water jugs, or clear plastic tubs. Ensure they have lids or can be modified to create a greenhouse effect. I prefer these gallon containers. They allow enough room for seedlings to grow and provide enough space for an adequate amount of soil.
Potting Soil: A lightweight, well-draining (preferably organic) potting soil mix.
Seeds: Choose varieties suited for winter sowing. Many seeds will specify that they need a period of cold stratification. Some do not. Refer to list below for additional guidance.
Tools: Scissors or a utility knife for cutting containers, a marker for labeling, and tape for sealing. Tape can be duct, packing, painting - anything that will stick.
Step-by-Step Guide to Winter Sowing
Prepare the Containers: Clean your chosen containers thoroughly. Cut them horizontally around the middle, leaving a small section attached to act as a hinge. Poke drainage holes in the bottom to prevent water accumulation.
Add Soil: Fill the bottom half of the container with about 3-4 inches of pre-moistened organic potting soil mix.
Sow the Seeds: Plant seeds according to the depth recommendations on the seed packet. Some seeds may require surface sowing, while others need to be buried.
Label: Clearly label each container with the plant name and sowing date using a waterproof marker. If you’re planting in December, you might want to add a label inside the container as well, so you ensure rain and snow doesn’t erase your label! It’s happened…
Seal the Container: Close the container and secure it with tape, leaving the top spout open or cutting ventilation holes to allow moisture and air exchange.
Place Outside: Set the containers in a location that receives sunlight and is exposed to rain and snow. Ensure they are protected from strong winds to prevent tipping.
Monitor: Check periodically to ensure the soil remains moist. As temperatures rise in spring, watch for germination. You’ll need to keep seedlings moist at this point if you don’t have enough rain. Once seedlings emerge and have two sets of true leaves, they can be transplanted into the garden (when they’re 1-2” tall).
Seeds and snow!
Best Plants for Winter Sowing
Many plants thrive with winter sowing, particularly those that are cold-hardy or require stratification. Here are some examples:
Perennials: Coneflower, milkweed, black-eyed susan, columbine, yarrow.
Annuals: Sunflower, cosmos, poppy, marigold, snapdragon.
Vegetables: Lettuce, spinach, kale, broccoli, cabbage, onions.
Herbs: Sage, dill, cilantro, parsley, oregano.
For an extensive list, check out the Facebook Winter Sowing group. https://www.facebook.com/groups/wintersown
Tips for Success
Timing: Begin winter sowing after the winter solstice, typically from late December to early February, depending on your climate.
Container Selection: Ensure containers are transparent enough to allow light penetration and have adequate drainage and ventilation.
Soil Moisture: Keep the soil moist but not waterlogged. Snowfall can help maintain moisture levels.
Acclimation: As seedlings grow and outdoor temperatures stabilize, keep an eye on the moisture level and plant outside when they’ve got 2 sets of true leaves.
Ready to plant!
Winter sowing is a rewarding technique that harnesses the natural rhythms of the seasons to produce strong, healthy plants. By following these steps, you can enjoy an early start to your gardening season with minimal effort and expense.
Inspired to grow your own garden this season? Whether you’re a beginner or looking to deepen your gardening skills, I’m here to help! Explore personalized coaching, workshops, and seasonal guidance designed just for you on my Work With Me page.
For a visual guide on winter sowing, you might find this video helpful:
Sources
Blackmore, Heather. (2024, January 17). Winter Sowing: A Budget Friendly Way to Start Seeds. https://hereshegrows.com/2024/01/17/winter-sowing/
Davidoff, Trudi. Winter Sowers - The Original. https://www.facebook.com/groups/wintersown
Jabbour, Niki. Winter Sowing. An Easy and Low-Cost Technique for Starting Seeds. https://savvygardening.com/winter-sowing/
Rutgers New Jersey Agricultural Experimentation Station. Guide to Winter Sowing. https://ocean.njaes.rutgers.edu/wp-content/uploads/2024/01/Winter-Seed-Sowing-Handout-Final.pdf
University of Illinois Urbana-Champaign, Illinois Extension. (2022, January 27). Seed stratification: What seeds require cold treatment. https://extension.illinois.edu/blogs/good-growing/2022-01-27-seed-stratification-what-seeds-require-cold-treatment
Wikipedia. Winter Sowing. https://en.wikipedia.org/wiki/Winter_sowing
Aloi, Peg. (2025, January 19). How to Get Started on Winter Sowing for Better Spring Blooms. https://www.thespruce.com/winter-sowing-8769838