We’re in our coldest weeks of winter, but you don’t need a windowsill to teach a lesson on gardening. Winter sowing is a garden practice that takes advantage of our cold and short winter days to “sync” plants with out season. Some of our native plants actually need this period of cold (called cold stratification) to signal that it’s time to sprout. For the purpose of this experiment, I’m using sugar snap peas because they’re tasty and one of the first veggies to sprout in the spring.

A common misconception is that seeds planted in winter will rot or sprout too early. In reality, sugar snap pea seeds are biologically programmed to wait.

While the bags are placed outside in January or February, the seeds will not sprout until the soil temperature inside the bag consistently reaches the 45°F to 55°F range, typically in March. This provides a clear visual representation of how plants use temperature to track the transition from winter to spring.

To begin winter sowing, gather the following supplies:

The plastic zip bag acts as a "mini-greenhouse," protecting the seeds from wind and pests. When the seeds begin to sprout, you’ll be able to monitor the progress and transplant them into their proper place in the garden.

1. Mark the bags

Mark the bags with information about how many seeds were planted and who planted them (as well as a date)

2. Add soil to the bags

The soil should be wet but not dripping when it’s held. Don’t fill the sandwich-sized bags more than 1/3 of the way with soil.

3. Add seeds

Plant a few seeds to the top of the soil.

4. Place Outdoors

The seeds will stay dormant in the bags all winter and sprout naturally as the weather warms up.

5. Replant.

In March when the seeds sprout their first true leaves, plant into a garden bed or a container outside. They’ll continue to grow even if there are frosts and freezes.

If you try this experiment, let us know how it goes! You can find me on Facebook or Instagram. Happy Gardening!