Nature designed seeds to recognize the optimum germinating conditions for healthy growth. Cold weather does not kill a healthy seed; too much water or not enough sunlight kills seeds. Too much water causes the seeds to rot in the soil. Many seeds, those tiny ones that look like dust at the bottom of a seed packet, need sunlight to germinate. Other seeds need stratification to germinate properly.
Stratification is the term used when a seed needs a period of cold temperatures and warmth to start the germination process. Winter sowing keeps the refrigerator drawer clear and allows you to stratify the seeds naturally.
Winter sowing your seeds also clears indoor space for other items and provides the seeds a chance to come into their own. There is no need to harden off the new plants before planting them in your garden. The outdoor temperatures and the protective planting environment, provided by winter sowing, gets the plants ready for outdoor growth in a natural setting.
To begin, gather growing containers of any shape, size and form. You can use empty milk jugs, two-liter soda bottles or even disposable take-out trays. Any container you can fill with planting soil and cover with plastic will work for winter sowing.
Prepare milk jugs by cutting around the jug, right below the bottom of the handle. Do not cut all the way through the container, but make it a flip-top, for easy access to the seedlings. You need duct tape to securely close the container, once the seeds are planted. For soda bottles, cut the bottle in half, about two thirds of the way down. For other containers, without lids, use a heavy plastic to cover the tops, once they are planted with seeds. Use a sharp knife to poke drainage holes in the bottom of the containers. Also make a few slits along the top or sides of the containers, for air circulation.
Use a quality potting soil to fill the containers. Avoid those potting soils that are made mostly from peat moss or don’t contain much soil. Winter sown seeds need plenty of good soil to grow strong roots. The soil needs to hold the moisture but also allow excess water to drain.
Choose viable, fresh seeds. You can either purchase new seeds or plant seeds you collected last growing season. The great thing about winter sowing is if you plant a seed and it doesn’t grow, you really didn’t invest a great deal of time. This is a set it and forget it method of growing.
Fill the containers with potting soil and plant the seeds according to the package directions. Water the seeds. Tape the containers closed or cover them with plastic. Set the containers in a protected area of your yard or along the north side of the house. The containers must receive at least six to eight hours of sunlight each day.
Let nature takes its course and watch for new plant growth, in the early spring. Once the weather permits, transplant the seedlings into separate containers or directly into your garden.