Starting seeds in the cold – Winter sowing
March 25, 2009
Winter sowing is a fairly new method of seed starting for seeds that require a cold period to germinate, such as Delphinium or Aquilegia (Columbine). This method can be done in January, February and March. Click here for a seed list of plants that should work well for winter sowing.
Clean, used plastic gallon milk containers, or bakery clam shells
Potting soil or Seed starting mix
Clear Duct tape
1. If using a milk jug, cut it in half, leaving one inch uncut right below the handle for a ‘hinge’. Cut several slits in the bottom for drainage. Discard cap off top of jug.
2. Add water to dampen your potting soil; moist enough that when you squeeze a handful it will clump together.
3. Fill the bottom of the milk jug with the dampened potting soil to a depth of 3 or 4 inches, pressing the soil firmly to pack.
4. To make rows, using a pen or pencil, press firmly into soil to make rows. (This is optional.)
5. Evenly distribute seeds onto soil or in the rows; for very small seeds hold the packet sideways while lightly tapping the top with your finger to control the flow of the seeds.
6. Spread a thin layer of dry seed starter over seeds; skip this step if the seeds require light to germinate.
7. Press down soil firmly over seeds to establish good soil contact with the seeds.
8. Lightly mist the entire top of the soil.
9. Place a label inside the container. I make mine from old plastic window blinds.
10. Using clear duct tape, tape top and bottom of milk jug together. Label the outside of the container with a permanent marker.
11. Place the jugs outside on the east, south or west side of your house; not in a protected area, making sure that rain or snow can reach the containers.
12. Watch containers for adequate moisture, condensation inside the jugs indicates enough moisture. If the soil appears dry, mist gently to moisten. As the weather warms up, check for germination and growth of plants. Cut extra holes to ensure plants do not overheat, and to help with the hardening off process. Around mid-May the covers can be completely removed, provided germination is complete.
I am trying it for the first time this year with a few perennial varieties of Delphinium and Columbine, and annual snapdragons. I will share the progress and results of how this new technique worked for me.
Update: this technique worked well, I think I would have had more success if I had used potting soil instead of soil starting mix. The soil starting mix is lighter and dried out fairly quick, I believe potting soil would have held moisture better and needed less watering. Next year I will try some on the north side of the house, I think they dried out to quick on the south side.