Native Plant Seeds are Ideal for Winter Sowing
Updated: Jan 15
OR Tips for Winter Sowing Native Plant Seeds Using Foil Roasting Pans With Lids. Winter sowing is a way to germinate seeds by mimicking the way they would grow in nature. By sowing seeds outside in ventilated containers, the germination rate is increased and the seeds are protected from disappearing in the garden or being eaten by any number of hungry critters. This method is designed for seeds that need the cold and moist cycle of winter conditions (stratification) before they can break dormancy and sprout when nature tells them to.
In the 20 years since Trudi Davidoff first coined the term, winter sowing has become wildly popular in gardening circles because it's not as fussy as growing seeds inside. It turns out winter sowing is a particularly ideal way to germinate native plants because they are growing in the regions where they would naturally exist; unlike non-native plants which would prefer to grow in the far away climates where they are from.
I now winter sow all my native seeds, including the warm season ones. They stay dormant in the winter and seem to know exactly when to sprout as the days get longer and the weather warms up. There are many great resources for how to winter sow. The main requirement is the containers be about 3-4 inches tall with drainage holes and a clear top with ventilation holes.
The most popular way to winter sow is using clear plastic milk jugs cut in half with holes poked in the bottom for drainage. The seeds are sown in the bottom half and duct tape secures the top. Preparing the jugs took me a long time because the plastic was thick and reusing them each year was kind of a pain.
A higher percentage of my seeds germinated in foil roasting pans with plastic covers than in the jugs.
It's also much easier to quickly cut slits in the pans with a utility knife for drainage and poke holes in the lids with a heated metal barbeque skewer (in a well ventilated place!) The pans can easily be reused each year. As an added benefit, I can divide the pans to create more biodiversity by planting many varieties of native plants.
I always seems to get the plastic and wooden stick labels mixed up by the time I need to transplant the seedlings, particularly when multiple varieties are in the same container. The game changer for me was using waterproof labels on the container itself. I can print out the common and botanical name as well as growing conditions which makes it easier when transplanting.
For soil, I use either all-purpose organic seed starting or potting soil. The list of what mediums not to winter sow in includes compost, garden soil, and mixes with fertilizers or moisture control added.
Native seeds can be sown a bit thick because this is the way they would naturally grow. Cover each seed according to the directions since some seeds don't even need to be covered. Sand is the best cover for the seeds but I use the soil I'm planting the seeds in and it seems to work just fine. The general rule is cover to the depth of the thickness of the seed meaning tiny seeds barely need to be covered.
Cover the container with plastic and seal it with small pieces of duct tape at the corners and in the center of each side then set outside in a shady location.
Once you put the containers outside, there’s nothing else to do until spring. The hardest and most exciting part of winter sowing is just waiting until little green seedlings pop up!