November 12, 2020

Winter Sowing

Calgary is the perfect place to Winter Sow.

Winter sowing can be done almost anywhere, anytime between late fall and early spring.

Winter sowing is a method that became popular by Trudi Davidoff, although gardeners around the globe have been using similar methods for generations.  Winter sowing is a method of sowing seeds under cover of plastic, glass or a grow cloth during the cold months and allowing them to naturally start without the use of a heated greenhouse or indoor planting. The is no need to stratifying seeds when winter sowing.

This list is broad on what can be “winter sown” and there is no better time to start than today!

There are two basic types of winter sowing and both methods work well.

Use a small container such as a plastic milk jug.  You will make a mini greenhouse from this jug so make sure it’s clean. 

  • Make a few holes close to the bottom of the jug with a nail or a hot soldering gun (About 2 cm from the bottom)
  • Label the type of seed you are sowing
  • Cut the jug just below the handle and add your growing medium
  • Plant your seeds into the soil, be careful to not overplant at this time, only add 9-12 seeds per jug for smaller plants, and for larger plants, 4-5 seeds is enough.
  • Tape jug closed using a strong tape such as duct tape.
  • Remove the lid from the jug.
  • Put your jug outside where it can get sun, snow but preferably out of the wind
  • Let nature do the rest.
  • In the spring, once seedlings start to grow, you may want to add more holes close to the top to allow for more light/moisture/air to circulate.
  • Most perennials will not need to be hardened off

For larger projects use a low tunnel. You can add a low tunnel to a raised garden bed, or directly on the garden bed.

  • This is the method we use at Rocky View Kitchen & Garden
  • Ensure your bed is worked well and soft enough for you to sow the seeds.
  • Create and insert your label makers
  • Sow your seeds ensuring that you leave room between seed types of about 10 cm.
  • Add your PVC pipes.
  • Cover a bed with thick clear plastic, you can use anything but greenhouse plastic will last for more years
  • Make sure your plastic can be tied at the ends, if you are sowing directly on the ground OR use a plastic-covered fitted end if you are sowing in a raised bed-you don’t want the cold blowing into your tunnel eliminating the greenhouse effect. 
  • Once seedlings emerge in spring, transplant your plants where desired, you will not need to harden off the seedlings.

Because seeds are living organisms, seeds have the ability to sense the environment around them, which allows them to determine when weather conditions are just right for germination. As a result, winter sown seeds often germinate earlier, have higher rates of germination and have fewer problems with seedling diseases such as damping off. They also tend to grow faster and stronger than their indoor-sown counterparts, which allows gardeners to get a jump on the growing season.

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