Winter Sowing: How to Sow Seeds in Winter

Winter sowing is a technique for starting plants from seed outdoors in the winter months rather than germinating them indoors and transplanting when the weather warms. To sow seeds in the winter, plant the seeds in miniature greenhouses and place the containers outdoors. The greenhouses, which you can make out of gallon milk jugs, offer a controlled environment and protect the seedlings from freezing temperatures. Winter sowing allows the natural conditions of your local climate to start the growth process. Winter sowing requires minimal effort and time, and produces hardy plants for your flower or vegetable garden.

The timeline for winter sowing depends on your climate and the types of plants you want to grow. For a cooler northern hemisphere climate, in USDA hardiness zones three through five, follow this timeline:

1. 1. January: You can sow perennials and cold-hardy annual flowers, like hollyhocks and coryopsis, in the month of January.
2. 2. February: Cold-weather veggies, such as broccoli, kale, Swiss chard, spinach, peas, and Brussels sprouts can begin in February. You can also start herbs such as thyme, sage, oregano, and cilantro, as well as flowers like calendula, delphinium, milkweed, morning glory, and snapdragon.
3. 3. March: Vegetables such as carrots, lettuce, bok choy, and beets are good to start in March, as well as tender herbs like basil and parsley. You can also start tender annual flowers, like marigolds and zinnias.
4. 4. April: In April, you can start planting tomatoes, onions, and peppers.

For warmer climates, many plants can begin as early as December. Check with your local gardening supply or the seed packets for specific recommendations.

Winter sowing is a great gardening technique for beginners and expert gardeners alike. Below is a step-by-step guide to starting your plants outside in wintertime:

1. 1. Buy your seeds. Seeds marked as “self-sowing,” “direct sow,” or “cold stratification” are best to use. Ask your local garden center about which type of seeds you can sow in the wintertime in your climate.
2. 2. Prep your miniature greenhouses. The key to successful winter sowing is moderating light, heat, and moisture. You can achieve this by making winter sowing containers, usually from repurposed plastic jugs. Two-liter soda bottles, gallon water jugs or milk jugs, or rotisserie chicken takeout containers all work. Be sure to thoroughly wash containers before planting.
3. 3. Drill and cut. Drill small drainage holes in the bottom of the containers or poke holes in the plastic with a hot screwdriver. Using a utility knife, cut the container one-third from the bottom to create two sections, the bottom and the lid.
4. 4. Prep your soil. A well-draining potting soil, such as those with peat moss or pearlite, works best for winter sowing. Pour the potting mix into the bottoms of the containers to a depth of two to three inches, then soak with water, allowing the water to drain afterward.
5. 5. Plant seeds. Spread the seeds evenly, and not too densely, before covering them with a bit of extra moistened soil.
6. 6. Adhere the lids. You can use duct tape to secure the container lids in place.
7. 7. Label your containers. Be sure to label each container with a permanent marker, so you’ll remember which one has which plant.
8. 8. Place the mini-greenhouses outside. If it snows where you live, place the planters in shallow plastic containers with drainage holes to collect moisture. Place the containers off the ground to help keep pests away.
9. 9. Check for moisture. In early spring, when the weather begins to warm, gently remove the tops of your mini-greenhouses. Check for moisture and add water if necessary. You should see seedlings beginning to sprout in the soil. As the weather gets warmer, you can leave the containers uncovered for longer periods during the day, just replace the tops at night.
10. 10. Transplant the seedlings into the garden. The process of transplanting varies from plant to plant, so be sure to check with your local gardening center or the seed packet instructions for the optimal time. In general, you can transplant winter-sown plants after it grows at least four leaves.

The winter sowing method can open up a new world of gardening possibilities. Consider the following list to see how you might benefit from getting your sowing started in the cold winter months:

1. 1. Low cost: Winter sowing requires minimal equipment. There is no need for grow lights, heating apparatus, fans, or other equipment that is needed for seed starting indoors.
2. 2. Simplicity: Winter sowing is a minimalist approach to gardening. It does not require a specialized technique or a lot of time for monitoring the plants. Once you’ve set things up, the growth process is straightforward.
3. 3. Naturally sustainable: Winter sowing closely mimics natural processes. This can be satisfying and educational, as you learn about ecology and horticulture.
4. 4. Early start: Avid gardeners in colder climates may find themselves restless in the long winter months, waiting for the last frost and the beginning of the outdoor growing season. Winter sowing allows gardeners to connect to the growing process earlier when outdoor plants are in dormancy.
5. 5. Robust plants: Traditional methods of starting seeds indoors usually involve a hardening-off period. This is when you place the plants outdoors in slightly warmer weather for progressively longer periods and bring them inside at night. This can be a tiring and error-prone process. Plants you winter sow will adjust naturally to the changing season.

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